Recent

  • Show all results for ""
System Design Chapter 1 Quiz
291 Questions
1 Views

System Design Chapter 1 Quiz

Created by
@EasiestMimosa

Questions and Answers

What is essential to ensure the smooth implementation of large scale software systems?

  • Writing code without design considerations
  • Avoiding user requirements analysis
  • First principles thinking in technical architecture (correct)
  • Focusing solely on algorithms and data structures

    • What do large enterprises need to carefully evaluate when designing software systems?

  • The latest programming languages
  • Trade-offs and user access patterns (correct)
  • Internal company politics
  • Social media trends

    • Why is understanding business requirements important in system design?

  • It reduces the need for error handling
  • It aligns the system with customer needs (correct)
  • It helps in feature bloat
  • It allows for faster coding without planning

    • What can enterprises avoid by investing time in understanding bottlenecks?

    <p>Inefficient software development efforts</p> Signup and view all the answers

    In the context of system design, what should be considered along with algorithms and data structures?

    <p>Futuristic changes and robustness</p> Signup and view all the answers

    What is a consequence of failing to properly design a large scale software system from the beginning?

    <p>Wasted software development efforts</p> Signup and view all the answers

    What is emphasized as a key aspect of designing technical architecture in system design?

    <p>Comprehensively evaluating systems</p> Signup and view all the answers

    Which of the following plays a critical role in the design phase of software development?

    <p>Understanding user objectives</p> Signup and view all the answers

    What is the main goal of understanding system design concepts?

    <p>To help with building large-scale software systems</p> Signup and view all the answers

    Which of the following statements best describes asynchronous communication?

    <p>It can happen without waiting for a reply.</p> Signup and view all the answers

    Which characteristic applies to synchronous communication?

    <p>It prevents further action until a response is received.</p> Signup and view all the answers

    In system design, what does consistency refer to?

    <p>The same data being viewed across all replica nodes at a given time.</p> Signup and view all the answers

    What is a primary benefit of asynchronous communication in system design?

    <p>It provides flexibility and tolerance for delays.</p> Signup and view all the answers

    Which aspect is NOT one of the fundamental concepts of system design?

    <p>Data warehousing</p> Signup and view all the answers

    When is synchronous communication typically preferred?

    <p>When real-time response is needed.</p> Signup and view all the answers

    What challenges are associated with consistency in distributed systems?

    <p>Keeping multiple replica nodes in sync with updates</p> Signup and view all the answers

    What is a common requirement for consistency regarding data storage and retrieval?

    <p>Each read must return the most recent value.</p> Signup and view all the answers

    Which scenario exemplifies asynchronous communication?

    <p>Email communication with a follow-up if no reply is received.</p> Signup and view all the answers

    What is a key characteristic of large-scale software systems?

    <p>They integrate multiple small sub-systems.</p> Signup and view all the answers

    In system design, what does fault tolerance refer to?

    <p>The capability to continue functioning despite failures.</p> Signup and view all the answers

    What is the purpose of using abstraction in system design?

    <p>To simplify and model complex system details.</p> Signup and view all the answers

    What is typically a consideration when deciding between synchronous and asynchronous communication?

    <p>Specific requirements and constraints of the system</p> Signup and view all the answers

    What is the primary purpose of redundancy in system availability?

    <p>To maintain functionality during a component failure</p> Signup and view all the answers

    What is a key characteristic of fault tolerance in a system?

    <p>It allows a system to operate despite errors or failures</p> Signup and view all the answers

    How does load balancing contribute to system availability?

    <p>By redistributing requests among multiple servers</p> Signup and view all the answers

    Which type of failover pattern involves multiple systems processing requests in parallel?

    <p>Active-active</p> Signup and view all the answers

    What is a potential drawback of an active-passive failover system?

    <p>Reduced availability during primary system failure</p> Signup and view all the answers

    In a multi leader replication pattern, what is a challenge that arises?

    <p>Conflicts and synchronization issues increase</p> Signup and view all the answers

    What is the main function of a single leader replication pattern?

    <p>To have one leader responsible for updates and followers for reads</p> Signup and view all the answers

    What happens if the leader system in a single leader replication pattern fails?

    <p>Data updates may be lost if not replicated</p> Signup and view all the answers

    Which of the following best describes the purpose of failover patterns?

    <p>To ensure continuous operation in case of a failure</p> Signup and view all the answers

    What is a common risk associated with both failover and replication patterns?

    <p>Complexity in implementation and management</p> Signup and view all the answers

    What is a major advantage of using multi leader replication over single leader replication?

    <p>Increased flexibility to read and write data</p> Signup and view all the answers

    Which approach effectively limits the risk of data loss in a failover system?

    <p>Implementing timely updates to followers</p> Signup and view all the answers

    What defines the active-active failover pattern?

    <p>All systems actively participate in processing</p> Signup and view all the answers

    Which aspect is crucial when choosing a failover pattern?

    <p>The desired level of availability and implementation costs</p> Signup and view all the answers

    What is the primary goal of data replication in distributed systems?

    <p>To maintain multiple copies of data across replica nodes.</p> Signup and view all the answers

    Which of these techniques helps recover data consistency after a system crash?

    <p>Write-ahead logging</p> Signup and view all the answers

    What does monotonic read consistency guarantee?

    <p>A client will never see outdated data on subsequent reads.</p> Signup and view all the answers

    Which consistency model guarantees that updates are immediately reflected across all replica nodes?

    <p>Strong consistency</p> Signup and view all the answers

    In which scenario would conflict resolution be necessary?

    <p>When two replica nodes attempt to update the same data at the same time.</p> Signup and view all the answers

    What role do consensus protocols play in distributed systems?

    <p>They ensure all nodes agree on updates to the data.</p> Signup and view all the answers

    Which technique involves assigning version numbers to write operations?

    <p>Data versioning</p> Signup and view all the answers

    What is a key characteristic of causal consistency?

    <p>It maintains the order of causally-related operations.</p> Signup and view all the answers

    What is the purpose of locking mechanisms in data storage systems?

    <p>To prevent multiple write operations from interfering with each other.</p> Signup and view all the answers

    Which of the following describes eventual consistency?

    <p>Updates may take time to be visible across all nodes.</p> Signup and view all the answers

    What is the impact of failures or delays in distributed systems?

    <p>They prevent data consistency across replica nodes.</p> Signup and view all the answers

    How does monotonic write consistency affect subsequent reads?

    <p>They will consistently reflect the latest acknowledged writes.</p> Signup and view all the answers

    What does the consistency spectrum model illustrate?

    <p>It describes different consistency guarantees in distributed systems.</p> Signup and view all the answers

    What is a common challenge in achieving strong consistency?

    <p>It requires all nodes to communicate simultaneously.</p> Signup and view all the answers

    What is a primary consequence of using multiple read replicas in a system?

    <p>Increased replication lag</p> Signup and view all the answers

    What typically limits the performance of read replicas compared to the leader system?

    <p>Leader systems execute writes in parallel</p> Signup and view all the answers

    Which metric is used to measure the average time a system can operate without failure?

    <p>Mean time between failures (MTBF)</p> Signup and view all the answers

    What does a low mean time to repair (MTTR) indicate about a system?

    <p>The system can be restored to operation quickly</p> Signup and view all the answers

    Which fallacy is associated with the assumption that network outages and packet losses are negligible?

    <p>Reliable Network</p> Signup and view all the answers

    How can reliability and availability be described in the context of system design?

    <p>Both can exist at high levels or be low simultaneously.</p> Signup and view all the answers

    What is vertical scaling primarily concerned with?

    <p>Increasing the resources of a single server</p> Signup and view all the answers

    What must be accounted for when designing systems to manage the inherent limitations of network data transfer speeds?

    <p>Latency</p> Signup and view all the answers

    Which fallacy refers to underestimating the security risks inherent in a distributed network?

    <p>Secure Network</p> Signup and view all the answers

    Which type of scaling is generally more cost-effective for unpredictable traffic patterns?

    <p>Horizontal scaling</p> Signup and view all the answers

    What essential component can help achieve high reliability and availability in a system?

    <p>Robust failover mechanisms</p> Signup and view all the answers

    How should systems be designed in relation to changing network conditions?

    <p>Be oblivious to topology changes</p> Signup and view all the answers

    Which of the following can indicate a system's reliability?

    <p>Mean time between failures (MTBF)</p> Signup and view all the answers

    Which of the following fallacies involves misjudging the costs associated with network infrastructure?

    <p>Zero Transport Cost</p> Signup and view all the answers

    What does horizontal scaling achieve in system design?

    <p>Adds more simple servers to meet load demands</p> Signup and view all the answers

    What is a primary consequence of the assumption that a network is homogenous?

    <p>Interoperability challenges</p> Signup and view all the answers

    When designing systems, why is it critical to account for potential network failure?

    <p>To ensure fault tolerance</p> Signup and view all the answers

    What is the impact of the number of read replicas on a system's processing capabilities?

    <p>May reduce the number of reads they can process</p> Signup and view all the answers

    In which scenario is vertical scaling typically most advantageous?

    <p>When load increases are foreseeable and manageable</p> Signup and view all the answers

    Which AWS Well-Architected Framework pillar is related to managing the fallacy of a single administrator?

    <p>Operational Excellence</p> Signup and view all the answers

    What is a key strategy to mitigate the effects of finite bandwidth in network designs?

    <p>Employing lightweight data formats</p> Signup and view all the answers

    What type of replication pattern can be more efficient for writes than read replicas?

    <p>Leader system replication</p> Signup and view all the answers

    What is a defining characteristic of a system with high reliability?

    <p>Longer operational periods without failure</p> Signup and view all the answers

    Which of these fallacies highlights the misconception about external threats to data integrity?

    <p>Secure Network</p> Signup and view all the answers

    What must systems ensure concerning network traffic due to the assumption of infinite bandwidth?

    <p>Avoidance of resource contention</p> Signup and view all the answers

    What principle helps counter the impact of latency in distributed systems?

    <p>Edge computing</p> Signup and view all the answers

    How can developers effectively handle the complexity introduced by multiple administrators in large systems?

    <p>Design in a decoupled manner</p> Signup and view all the answers

    Which fallacy involves the assumption that the network configuration remains stable over time?

    <p>Fixed Topology</p> Signup and view all the answers

    What does eventual consistency guarantee in a distributed system?

    <p>Given enough time, all replica nodes will eventually have the same view of the data.</p> Signup and view all the answers

    How is availability typically quantified in a system?

    <p>As the percentage of time the system is operational over a specific period.</p> Signup and view all the answers

    What is the goal for achieving high availability typically measured in?

    <p>Nines, such as five nines.</p> Signup and view all the answers

    What happens when components with 99.9% availability are arranged in sequence?

    <p>The overall availability is calculated as the product of their individual availabilities.</p> Signup and view all the answers

    In terms of data consistency, what does strong consistency ensure?

    <p>The order of operations is preserved and visible immediately to all nodes.</p> Signup and view all the answers

    Which of the following could make achieving higher levels of availability more difficult?

    <p>Resource constraints for maintenance and redundancy.</p> Signup and view all the answers

    What is an example of a system that might strive for very high availability levels?

    <p>Financial trading platforms.</p> Signup and view all the answers

    What is the expected result of querying a node under eventual consistency before all replicas are synchronized?

    <p>The system may return stale data.</p> Signup and view all the answers

    How does parallel arrangement affect the overall availability of system components?

    <p>It increases total availability significantly.</p> Signup and view all the answers

    What happens when aiming to increase availability by adding more 'nines'?

    <p>Each additional nine demands exponential increases in resources.</p> Signup and view all the answers

    Which of the following is true about a system's availability during high load or errors?

    <p>A highly available system should process requests in a timely fashion even under such conditions.</p> Signup and view all the answers

    What is the relationship between the components arranged in a sequential system and their overall availability?

    <p>The overall availability is the product of the individual availabilities.</p> Signup and view all the answers

    What does a system designer consider when choosing a consistency model?

    <p>Trade-offs between consistency and availability.</p> Signup and view all the answers

    What is a primary advantage of horizontal scaling in managing unpredictable traffic?

    <p>It allows for cost-effective handling of increased requests.</p> Signup and view all the answers

    Which of the following aspects must be covered to ensure a software system is maintainable?

    <p>Operability, Lucidity, Modifiability</p> Signup and view all the answers

    Which feature of a distributed system ensures order preservation of updates?

    <p>Strong consistency.</p> Signup and view all the answers

    What is the main goal of fault tolerance in large-scale systems?

    <p>To ensure continuous service amid hardware or software failures.</p> Signup and view all the answers

    How does replication contribute to fault tolerance?

    <p>By duplicating nodes and data across multiple storage locations.</p> Signup and view all the answers

    What characterizes synchronous checkpointing in a system?

    <p>It necessitates halting all data mutations until completion.</p> Signup and view all the answers

    Why is modifiability important in system design?

    <p>To enable easy modifications without disrupting subsystems.</p> Signup and view all the answers

    What does lucidity in a system primarily ensure?

    <p>Ease of understanding and collaboration among team members.</p> Signup and view all the answers

    What is a disadvantage of asynchronous checkpointing?

    <p>It can lead to inconsistent data states across servers.</p> Signup and view all the answers

    Which scaling method is recommended for early-stage systems before moving to horizontal scaling?

    <p>Vertical scaling with improved configurations.</p> Signup and view all the answers

    What is a key characteristic of operability in system design?

    <p>The system should return to normal operations swiftly after faults.</p> Signup and view all the answers

    What is the primary purpose of checkpointing in large-scale systems?

    <p>To ensure data reliability and integrity.</p> Signup and view all the answers

    What is a fundamental challenge of horizontal scaling?

    <p>It complicates the management of multiple servers.</p> Signup and view all the answers

    Which technology can enhance the durability of a database during failures?

    <p>Checkpointing mechanisms</p> Signup and view all the answers

    What does fault tolerance help prevent in large-scale systems?

    <p>Loss of data due to server downtimes.</p> Signup and view all the answers

    What is crucial for the successful implementation of large scale software systems?

    <p>First principles thinking in technical architecture</p> Signup and view all the answers

    Which aspect is NOT considered when designing large scale software systems?

    <p>Peer programming techniques</p> Signup and view all the answers

    What should enterprises evaluate to avoid wasted software development effort?

    <p>System requirements and bottlenecks</p> Signup and view all the answers

    What is the result of a well-designed technical architecture in large scale software systems?

    <p>A smooth implementation journey</p> Signup and view all the answers

    Which of the following best describes a key consideration in system design?

    <p>Contemplating futuristic changes</p> Signup and view all the answers

    What primary focus should enterprises have while designing large scale software systems?

    <p>Thoroughly understanding user requirements</p> Signup and view all the answers

    What is a potential consequence of neglecting design considerations in large scale system software?

    <p>Unpredictable user experiences</p> Signup and view all the answers

    What role does understanding business requirements play in system design?

    <p>It informs the technical architecture and user needs</p> Signup and view all the answers

    What is the main focus when balancing the trade-offs in system design?

    <p>Creating a system optimized for user needs</p> Signup and view all the answers

    Which factor is NOT mentioned as a consideration in system design trade-offs?

    <p>Interoperability</p> Signup and view all the answers

    How does bandwidth fundamentally differ from throughput?

    <p>Bandwidth pertains to maximum capacity; throughput is actual data processed.</p> Signup and view all the answers

    What is a common consequence of insufficient bandwidth?

    <p>Network congestion</p> Signup and view all the answers

    In the context of latency and throughput, what happens as latency increases?

    <p>Throughput decreases as latency increases</p> Signup and view all the answers

    Which metric is recommended to capture latency in a system under load?

    <p>Percentiles such as p90</p> Signup and view all the answers

    What is the trade-off described by the CAP theorem?

    <p>Consistency vs Availability</p> Signup and view all the answers

    When considering performance vs scalability, what indicates a performance issue?

    <p>Sluggish response times for a single user</p> Signup and view all the answers

    What is the relationship between latency and throughput?

    <p>Inverse relationship</p> Signup and view all the answers

    Which trade-off is a key consideration when designing a system with scalability in mind?

    <p>Performance vs Load capacity</p> Signup and view all the answers

    Which of the following is a characteristic of a system that prioritizes maintainability?

    <p>Easily understandable code</p> Signup and view all the answers

    In terms of system design trade-offs, what might sacrificing robustness typically lead to?

    <p>Lower costs but increased errors</p> Signup and view all the answers

    What can using look-up tables in an algorithm help achieve in system design?

    <p>Faster request serving through pre-calculated values</p> Signup and view all the answers

    What is a potential downside of focusing too heavily on cost in system design?

    <p>Compromised performance and robustness</p> Signup and view all the answers

    What does the KISS guideline emphasize in system design?

    <p>Creating simple and efficient systems</p> Signup and view all the answers

    Which of the following best defines metrics in the context of system performance?

    <p>Quantitative measures to assess system performance</p> Signup and view all the answers

    What is the significance of observability in large-scale systems?

    <p>It enables real-time monitoring and diagnosis of issues.</p> Signup and view all the answers

    What does TINSTAAFL advocate regarding system design decisions?

    <p>Each decision comes with trade-offs.</p> Signup and view all the answers

    What does the CAP theorem state regarding distributed systems?

    <p>A distributed system can provide at most two of the three guarantees at any time.</p> Signup and view all the answers

    Which statement most accurately describes a fundamental aspect of system design?

    <p>System design must balance competing factors and trade-offs.</p> Signup and view all the answers

    According to the PACELC theorem, what must be chosen in the absence of network partitions?

    <p>Latency or Consistency</p> Signup and view all the answers

    In system design, what role do performance metrics play?

    <p>They help identify trends and detect anomalies.</p> Signup and view all the answers

    Which aspect does observing and measuring metrics not help with in system design?

    <p>Identifying user preferences directly</p> Signup and view all the answers

    What trade-off does the CAP theorem highlight during network failures?

    <p>Consistency must be chosen over availability.</p> Signup and view all the answers

    Why is building a system modularly beneficial?

    <p>It allows for independent testing and validation of modules.</p> Signup and view all the answers

    What does the concept of 'it always depends' suggest in system design?

    <p>Multiple factors influence design choices.</p> Signup and view all the answers

    What is emphasized in the guideline of simplicity in system design?

    <p>Avoiding unnecessary complexity and over-engineering.</p> Signup and view all the answers

    Why is it important to weigh trade-offs in system design?

    <p>To develop systems that meet specific project requirements.</p> Signup and view all the answers

    Which aspect is not specifically mentioned as a characteristic of modular systems?

    <p>Performance</p> Signup and view all the answers

    What can be a consequence of failing to think about trade-offs in system design?

    <p>Poor performance or reliability issues in the final system.</p> Signup and view all the answers

    What happens if a system pursues strong consistency through synchronous communication?

    <p>It adds to high latency.</p> Signup and view all the answers

    What is the primary focus when measuring system performance?

    <p>Quantitative evaluation of key performance indicators.</p> Signup and view all the answers

    How can observability affect system reliability?

    <p>By allowing real-time detection of potential issues.</p> Signup and view all the answers

    What principle is highlighted in the guideline of isolation?

    <p>Create independent components to reduce complexity.</p> Signup and view all the answers

    What often results from choosing a simpler design solution?

    <p>Lower performance or increased latency.</p> Signup and view all the answers

    What does eventual consistency imply in distributed systems?

    <p>Data will eventually reflect the latest write after some time.</p> Signup and view all the answers

    What is a potential trade-off in achieving high levels of system performance?

    <p>Higher complexity in the design.</p> Signup and view all the answers

    Which statement about the PACELC theorem is accurate?

    <p>It provides a framework for understanding trade-offs in normal operation and during partitioning.</p> Signup and view all the answers

    What guideline advises to ensure easy usability of the system?

    <p>Guideline of Simplicity</p> Signup and view all the answers

    Which factor is crucial when designing modular systems according to the content?

    <p>Controlling data flows and dependencies between modules.</p> Signup and view all the answers

    What characterizes systems that are designed using the PACELC theorem?

    <p>They involve a choice between availability and consistency during partitions and latency and consistency otherwise.</p> Signup and view all the answers

    Which principle ensures that modules can be reused in different projects?

    <p>Modularity</p> Signup and view all the answers

    What is the primary characteristic of synchronous communication in system design?

    <p>It blocks the sender until a response is received.</p> Signup and view all the answers

    Which of the following best describes the difference between synchronous and asynchronous communication?

    <p>Synchronous waits for a reply while asynchronous does not.</p> Signup and view all the answers

    In the context of data storage, what does consistency ensure?

    <p>Data updates are reflected immediately across all nodes.</p> Signup and view all the answers

    What is an example of asynchronous communication?

    <p>Sending a text message and waiting for a reply.</p> Signup and view all the answers

    Which concept refers to the ability of a system to continue operating in the event of a failure?

    <p>Fault tolerance</p> Signup and view all the answers

    When is synchronous communication most appropriately used in a software system?

    <p>When immediate feedback is necessary.</p> Signup and view all the answers

    What is meant by 'abstraction' in system design?

    <p>The process of eliminating complexity in systems.</p> Signup and view all the answers

    What does scalability refer to in system design?

    <p>The potential to add resources to meet increasing demands.</p> Signup and view all the answers

    In distributed systems, what does a consistency issue often refer to?

    <p>Replica nodes not having the same view of data.</p> Signup and view all the answers

    Why is asynchronous communication considered flexible?

    <p>It does not require simultaneous user presence.</p> Signup and view all the answers

    What is a common challenge associated with consistency in large-scale systems?

    <p>Maintaining uniformity across geographically dispersed nodes.</p> Signup and view all the answers

    What role does 'fault tolerance' play in system design?

    <p>It allows systems to recover from or continue despite failures.</p> Signup and view all the answers

    What aspect of system design is concerned with how effectively a system can remain available?

    <p>Reliability</p> Signup and view all the answers

    Why might a system designer choose asynchronous communication over synchronous?

    <p>To allow processes to proceed without waiting for feedback.</p> Signup and view all the answers

    What technique is primarily used to log writes before applying them to data?

    <p>Write-ahead logging</p> Signup and view all the answers

    Which of the following models ensures that once a client reads a value, all subsequent reads return the same or a more recent value?

    <p>Monotonic read consistency</p> Signup and view all the answers

    What is used to resolve conflicts when multiple replica nodes attempt to update the same data simultaneously?

    <p>Conflict resolution algorithms</p> Signup and view all the answers

    Which consistency level guarantees that all replica nodes reflect the same data at all times?

    <p>Strong consistency</p> Signup and view all the answers

    What does locking in data storage systems primarily ensure?

    <p>Only one write operation can occur at a time</p> Signup and view all the answers

    What is the primary purpose of consensus protocols in distributed systems?

    <p>To ensure all replica nodes agree on updates</p> Signup and view all the answers

    What technique allows concurrent writes while ensuring reads return the most recent write?

    <p>Data versioning</p> Signup and view all the answers

    What does causal consistency guarantee in the context of operations?

    <p>Dependent operations are preserved in order</p> Signup and view all the answers

    Which statement best describes 'eventual consistency'?

    <p>Data may be temporarily inconsistent but will converge to a consistent state eventually</p> Signup and view all the answers

    What is the primary challenge when implementing strong consistency in distributed systems?

    <p>Constant communication among all replica nodes</p> Signup and view all the answers

    What does monotonic write consistency ensure about write operations?

    <p>Once acknowledged, all subsequent reads reflect the updated value</p> Signup and view all the answers

    Which technique is fundamental for restoring data consistency after a system crash?

    <p>Write-ahead logging</p> Signup and view all the answers

    What does the consistency spectrum model help reason about in distributed systems?

    <p>The various consistency guarantees offered by the system</p> Signup and view all the answers

    Which of the following describes the active-passive failover pattern?

    <p>One primary system actively processes requests while backup systems are passive.</p> Signup and view all the answers

    What is a potential issue with multi leader replication?

    <p>Increased risk of data consistency due to conflicting writes.</p> Signup and view all the answers

    Which technique is primarily used to improve system availability?

    <p>Load balancing</p> Signup and view all the answers

    In the context of failover systems, what is the primary advantage of the active-active pattern?

    <p>Higher flexibility and better resource utilization.</p> Signup and view all the answers

    What can be a consequence of using single leader replication?

    <p>Possibility of reduced availability if the leader fails.</p> Signup and view all the answers

    Which of the following is NOT a technique to enhance system availability?

    <p>Error-prone coding</p> Signup and view all the answers

    What is a key trade-off of an active-active failover system?

    <p>Higher costs due to redundancy in resources.</p> Signup and view all the answers

    How does replication contribute to system availability?

    <p>By maintaining multiple copies of data to prevent failure.</p> Signup and view all the answers

    What is a characteristic of the active-active failover strategy?

    <p>Complex management is required due to simultaneous activity.</p> Signup and view all the answers

    What role does load balancing play in system design?

    <p>Distributing workload across multiple resources to enhance efficiency.</p> Signup and view all the answers

    Which of the following can lead to data loss in failover systems?

    <p>Failing to properly manage backup activation timings.</p> Signup and view all the answers

    What is the primary objective of using redundancy in a system?

    <p>To maintain functionality despite component failures.</p> Signup and view all the answers

    Which type of replication pattern allows writing to multiple systems at the same time?

    <p>Multi leader replication</p> Signup and view all the answers

    What effect does the use of multiple read replicas have on replication lag?

    <p>It increases replication lag due to more writes needing replication.</p> Signup and view all the answers

    Which of the following best defines reliability in system design?

    <p>The system's ability to perform functions consistently over time.</p> Signup and view all the answers

    What does the term Mean Time Between Failures (MTBF) measure?

    <p>The average time a system operates without experiencing a failure.</p> Signup and view all the answers

    How is Mean Time to Repair (MTTR) characterized?

    <p>It is the average time required to repair a system after a failure.</p> Signup and view all the answers

    Which is true about the relationship between reliability and availability?

    <p>A system can be reliable but not available at the same time.</p> Signup and view all the answers

    What is vertical scaling in the context of system design?

    <p>Upgrading a single server with better resources to handle load.</p> Signup and view all the answers

    What advantage does horizontal scaling offer over vertical scaling?

    <p>It is less costly than upgrading a single high-end server.</p> Signup and view all the answers

    In which scenario is vertical scaling particularly useful?

    <p>When traffic is predictable and can be handled by a stronger server.</p> Signup and view all the answers

    What challenge arises with the use of multiple read replicas?

    <p>It complicates the process of write replication.</p> Signup and view all the answers

    What does scalability in system design ensure?

    <p>The system's performance improves as more resources are added.</p> Signup and view all the answers

    Which of the following statements is true regarding the implementation of redundancy?

    <p>Redundancy is vital for achieving high reliability and availability.</p> Signup and view all the answers

    What is the overall goal of using MTBF and MTTR measurements in a system?

    <p>To measure and enhance the reliability of the system.</p> Signup and view all the answers

    Which challenge is associated with vertical scaling?

    <p>Limits on how much a single server can scale up.</p> Signup and view all the answers

    What does eventual consistency guarantee in a distributed system?

    <p>Data may be temporarily inconsistent before reconciliation.</p> Signup and view all the answers

    Which metric is used to quantify the availability of a system?

    <p>Total system uptime as a percentage of total operational time.</p> Signup and view all the answers

    What is the primary trade-off involved in the consistency spectrum model?

    <p>Consistency vs. availability in system design.</p> Signup and view all the answers

    Which of the following scenarios describes a system with high availability?

    <p>The system shows some downtime but remains functional under stress.</p> Signup and view all the answers

    How does the arrangement of components in a system affect overall availability?

    <p>Components in parallel can lead to higher total availability than identical components in sequence.</p> Signup and view all the answers

    What is a key challenge in achieving 'five nines' availability?

    <p>Higher levels of redundancy and rigorous maintenance are needed.</p> Signup and view all the answers

    If two components both have an availability of 99.9% and are arranged in sequence, what will be the overall availability?

    <p>99.8%</p> Signup and view all the answers

    Which factor does NOT affect the realism of achieving high levels of availability?

    <p>Consumer demand for quicker transactions.</p> Signup and view all the answers

    What does the term 'availability percentages represented in 9s' indicate?

    <p>The duration of downtime over a specified period.</p> Signup and view all the answers

    What is commonly involved in maintaining high availability in a system?

    <p>Redundant components and continuous monitoring.</p> Signup and view all the answers

    What does a higher level of availability often require regarding system architecture?

    <p>More complex architectures with extensive redundancies.</p> Signup and view all the answers

    What is the implication of assuming that the network is reliable in distributed system design?

    <p>It leads to potential failures due to unforeseen network outages.</p> Signup and view all the answers

    Why is the assumption that latency is zero problematic in distributed systems?

    <p>It ignores the physical limitations of data transmission.</p> Signup and view all the answers

    What happens to the overall availability in a sequential system if one component fails?

    <p>Overall availability drops to zero.</p> Signup and view all the answers

    Which of the following describes the primary difference between strong consistency and eventual consistency?

    <p>Strong consistency guarantees immediate data replication while eventual consistency does not.</p> Signup and view all the answers

    What consequence might arise from assuming infinite bandwidth in network design?

    <p>It can lead to unmanageable data flow and subsequent packet loss.</p> Signup and view all the answers

    Which fallacy relates to the misconception that network security is guaranteed?

    <p>Secure Network</p> Signup and view all the answers

    What is a consequence of arranging components in a sequential system?

    <p>Increased latency due to waiting on responses.</p> Signup and view all the answers

    How does the assumption of a fixed topology complicate distributed system design?

    <p>It fails to account for changes in node availability.</p> Signup and view all the answers

    What is a primary concern when inferring a single administrator for distributed systems?

    <p>It underestimates the complexity of system management.</p> Signup and view all the answers

    What does the assumption of zero transport cost overlook in network design?

    <p>The cumulative expenses involved in network infrastructure maintenance.</p> Signup and view all the answers

    Why is it important to account for a heterogeneous network when designing distributed systems?

    <p>It enables interoperability among differing systems and protocols.</p> Signup and view all the answers

    What might be a direct result of neglecting the fallacies in distributed systems during implementation?

    <p>Higher likelihood of system failures and performance bottlenecks.</p> Signup and view all the answers

    Which AWS Well-Architected Framework pillar addresses the fallacy of assuming a secure network?

    <p>Security</p> Signup and view all the answers

    How can the assumption of network reliability impact system administration complexity?

    <p>It can lead to oversights in necessary maintenance routines.</p> Signup and view all the answers

    What approach can help mitigate the risks associated with assuming zero latency in distributed systems?

    <p>Implementing edge computing solutions.</p> Signup and view all the answers

    What is a potential effect of neglecting the fallacy of infinite bandwidth in distributed network designs?

    <p>Increased likelihood of network congestion and data losses.</p> Signup and view all the answers

    What is a primary benefit of horizontal scaling for managing unpredictable traffic?

    <p>It increases server capacity to handle more requests.</p> Signup and view all the answers

    What aspect of maintainability involves a system being easy to modify or extend?

    <p>Modifiability</p> Signup and view all the answers

    Which mechanism ensures that a system can recover from a failure and continue to serve requests?

    <p>Replication</p> Signup and view all the answers

    What does synchronous checkpointing require from the system during the checkpointing process?

    <p>Only read requests are allowed.</p> Signup and view all the answers

    Which of the following is NOT a component of maintainability in system design?

    <p>Inflexibility</p> Signup and view all the answers

    What is a primary risk associated with asynchronous checkpointing?

    <p>It can create inconsistent data states across servers.</p> Signup and view all the answers

    Which aspect of a system does operability emphasize on?

    <p>Smooth operation under normal conditions</p> Signup and view all the answers

    To adapt to changing business needs, software systems must prioritize which of these aspects?

    <p>Modifiability</p> Signup and view all the answers

    How does replication contribute to fault tolerance?

    <p>By duplicating services and data across multiple servers.</p> Signup and view all the answers

    What is the main function of checkpointing in a system?

    <p>To ensure data integrity and reliability.</p> Signup and view all the answers

    In large-scale systems, what does fault tolerance primarily aim to eliminate?

    <p>Single points of failure</p> Signup and view all the answers

    What is the role of lucidity in a software system?

    <p>To enhance understanding and collaboration among team members.</p> Signup and view all the answers

    Which of the following is a vital characteristic of highly maintainable systems?

    <p>Modular design</p> Signup and view all the answers

    What is the purpose of having multiple copies of data in replication?

    <p>To ensure data availability and recovery during failures.</p> Signup and view all the answers

    What is the primary goal when balancing trade-offs in system design?

    <p>To optimize for user needs without sacrificing critical factors</p> Signup and view all the answers

    What does the CAP theorem address in system design?

    <p>The balance between consistency and high availability</p> Signup and view all the answers

    Which trade-off involves managing the speed of requests versus the ability to handle increased demand?

    <p>Performance vs Scalability</p> Signup and view all the answers

    Which metric is more empirical and measures actual data transmission in a network?

    <p>Throughput</p> Signup and view all the answers

    What does it mean if a system is experiencing high latency?

    <p>Requests are delayed and waiting to be handled</p> Signup and view all the answers

    If a system prioritizes cost, which of the following factors may be sacrificed?

    <p>All of the above</p> Signup and view all the answers

    Which of the following best defines latency in a network context?

    <p>The time a request waits to be handled</p> Signup and view all the answers

    What happens to throughput as latency increases?

    <p>Throughput decreases</p> Signup and view all the answers

    A system that is designed for both high reliability and scalability may result in which trade-off?

    <p>Increased need for expensive components</p> Signup and view all the answers

    Why is average latency not used as a metric in system design?

    <p>It can be affected by outliers</p> Signup and view all the answers

    In what situation might you prioritize scalability over performance?

    <p>In an environment anticipating rapid growth in user demand</p> Signup and view all the answers

    Which of these concepts relates to the actual capacity of a network under specific conditions?

    <p>Throughput</p> Signup and view all the answers

    Which of the following accurately captures the relationship between latency and throughput?

    <p>They have an inverse relationship</p> Signup and view all the answers

    What would likely be a consequence of insufficient bandwidth in a network?

    <p>Network congestion and slow connectivity</p> Signup and view all the answers

    Which guarantees can a distributed system provide simultaneously according to the CAP theorem?

    <p>Consistency and Partition Tolerance</p> Signup and view all the answers

    When a network partition occurs, what trade-off must a distributed system make according to the CAP theorem?

    <p>Consistency and Availability</p> Signup and view all the answers

    What does the PACELC theorem specify when there are no network partitions?

    <p>Choose between consistency and latency</p> Signup and view all the answers

    Which guideline focuses on restructuring a system into smaller independent components?

    <p>Guideline of Isolation</p> Signup and view all the answers

    Which approach supports reusability in system design?

    <p>Modular system design</p> Signup and view all the answers

    What is the main consequence of prioritizing complexity over simplicity in system design?

    <p>Difficulty in understanding and use</p> Signup and view all the answers

    What is a characteristic of synchronous communication within a distributed system?

    <p>All parties must be available and responsive</p> Signup and view all the answers

    Which of the following would NOT align with the Keep it Simple, Silly (KISS) principle in system design?

    <p>Adding numerous unnecessary features</p> Signup and view all the answers

    Which is a key advantage of maintaining modularity in a system design?

    <p>Reduced risk of system-wide failures</p> Signup and view all the answers

    Why might a team opt for eventual consistency in a distributed system?

    <p>To enable higher performance with lower latency</p> Signup and view all the answers

    What aspect should be prioritized when designing to accommodate growth in large scale systems?

    <p>Scalability of components</p> Signup and view all the answers

    Which of the following statements best reflects the purpose of the CAP theorem in system design?

    <p>Describes trade-offs among consistency, availability, and partition tolerance</p> Signup and view all the answers

    What could be a negative outcome of excessive modularity in system design?

    <p>Increased difficulty in managing module interfaces</p> Signup and view all the answers

    What does the KISS guideline emphasize in system design?

    <p>Creating simple, efficient, and maintainable systems</p> Signup and view all the answers

    Which of the following best describes observability in system design?

    <p>Inferring the state of a system from its outputs</p> Signup and view all the answers

    What does TINSTAAFL imply in system design?

    <p>Optimizing for one aspect may compromise another</p> Signup and view all the answers

    Which of the following is NOT a factor considered in system design?

    <p>Personal preferences of the developer</p> Signup and view all the answers

    How do metrics contribute to system performance management?

    <p>By tracking key performance indicators</p> Signup and view all the answers

    Why is it necessary to measure before building systems?

    <p>To gather data that informs decisions and optimizations</p> Signup and view all the answers

    In system design, what is the significance of balancing competing factors?

    <p>It helps in producing systems that meet specific requirements</p> Signup and view all the answers

    What happens when simplicity is prioritized excessively in system design?

    <p>Reduction in maintainability and increase in complexity</p> Signup and view all the answers

    What role does observability play in managing large-scale systems?

    <p>To allow detection of real-time issues impacting performance</p> Signup and view all the answers

    Which statement illustrates the importance of trade-offs in system design?

    <p>Optimizing one aspect often detracts from others.</p> Signup and view all the answers

    What is implied by the statement, 'It always depends' in system design?

    <p>All design choices are context-dependent.</p> Signup and view all the answers

    How can metrics and observability work together in system design?

    <p>Metrics provide quantitative data, while observability aids in diagnostics.</p> Signup and view all the answers

    What should system designers recognize about solutions in the context of trade-offs?

    <p>Solutions must consider potential trade-offs and implications.</p> Signup and view all the answers

    What can be a likely consequence of neglecting performance metrics?

    <p>Failure to identify performance bottlenecks</p> Signup and view all the answers

    Study Notes

    System Design Overview

    • Large-scale software systems are fundamental to modern technological advancements, evidenced by companies like Google, Amazon, Oracle, and SAP.
    • First principles thinking is critical in designing technical architecture to prevent issues later in the implementation process.

    Importance of System Design

    • Successful system design focuses on business requirements, customer needs, and various trade-offs to ensure long-term functionality.
    • Careful consideration of system bottlenecks and user access patterns is essential for effective system design.

    Foundational Concepts in System Design

    • Key concepts include:
      • Communication
      • Consistency
      • Availability
      • Reliability
      • Scalability
      • Fault tolerance
      • System maintainability

    Communication Mechanisms

    • Synchronous Communication:

      • Example: Real-time phone conversations where both parties communicate simultaneously.
      • The application waits for responses before proceeding, potentially causing perceived latency.

    • Asynchronous Communication:

      • Example: Email exchanges allowing delayed responses.
      • The sender does not wait for replies, facilitating flexibility and resilience in applications.

    Consistency in Systems

    • Consistency ensures all parts of a distributed system view data uniformly, pertinent in contexts like data storage and retrieval.
    • Consistency Techniques in distributed systems:
      • Data Replication: Multiple replicas are updated simultaneously for uniformity.
      • Consensus Protocols: Ensure agreement on data updates among nodes.
      • Conflict Resolution: Mechanisms to handle simultaneous conflicting updates from different replicas.

    Consistency in Data Storage

    • Techniques to maintain consistency in data storage include:
      • Write-ahead Logging: Logs write operations before application to data.
      • Locking Mechanisms: Control concurrent write access.
      • Data Versioning: Allows multiple concurrent writes while preserving read consistency.

    Consistency Spectrum Model

    • Consistency ranges from Eventual Consistency (leading to flexibility with potential data stale states) to Strong Consistency (ensuring all replicas are updated immediately after a write).

    Availability in Systems

    • Availability measures a system's capacity to serve requests effectively, even under failures.
    • Calculated as the proportion of uptime to total operational time, expressed as a percentage of the “nines” (e.g., 99.9999% represents six nines).

    Achieving High Availability

    • Each increment in availability comes with increased cost and complexity.
    • Techniques include:
      • Redundancy: Having backup components to maintain function amid failures.
      • Fault Tolerance: System resilience against unpredictable errors.

    System Arrangement Impacting Availability

    • Sequential Systems: The overall availability is multiplied across components; e.g., two 99.9% components yield 99.8% availability.
    • Parallel Systems: Availability is significantly improved as components can serve requests simultaneously, leading to a maintained uptime (e.g., two 99.9% components yield 99.9999% availability).

    Ensuring System Availability

    • Critical for maintaining performance and reliability through methods like redundancy and fault tolerance to navigate failure scenarios effectively.### Availability Mechanisms
    • Systems can achieve high availability through error-handling mechanisms, redundant hardware, or self-healing systems.
    • Load balancing distributes incoming requests across multiple servers to efficiently manage heavy loads and enhance availability.
    • Active-active and active-passive are the two primary failover patterns utilized to maintain system availability.

    Failover Patterns

    • Active-active failover: Multiple systems process requests in parallel; if one fails, others continue operations, providing flexibility but increasing complexity.
    • Active-passive failover: One primary system handles requests while passive backups wait to take over if the primary fails. This method is simpler but can cause delays during failover, reducing availability.

    Replication Patterns

    • Replication maintains multiple data copies to enhance availability and fault tolerance, with multi-leader and single-leader formats being the two main types.
    • Multi-leader replication: Multiple systems can read and write data, offering flexibility but increasing complexity and potential latency due to conflict resolution.
    • Single-leader replication: A single leader manages commands while followers replicate data for read operations only. This approach risks data loss if the leader fails and can lead to replication lag.

    Reliability Measurement

    • Reliability reflects a system's consistency in performing intended functions. Key metrics include:
      • Mean Time Between Failures (MTBF): Time a system operates without failure; higher is more reliable.
      • Mean Time to Repair (MTTR): Time to restore a system after failure; lower is better.

    Reliability vs. Availability

    • Reliability and availability are interrelated; a reliable but unavailable system fails at critical times, while an available but unreliable system may perform erratically.
    • Meeting service level objectives (SLOs) requires incorporating redundancy and failover mechanisms alongside regular maintenance.

    Scalability

    • Scalability ensures system performance improves with additional resources in response to increased workloads, whether from user requests or data storage needs.
    • Vertical scaling enhances a single server's capabilities but has limits and high costs associated with resource upgrades.
    • Horizontal scaling involves adding multiple servers, providing cost-effective scalability for variable traffic levels but adds management complexity.

    Maintainability

    • Maintainability allows a system to adapt to changing user needs without disrupting operations. Three key aspects include:
      • Operability: The system should function smoothly and resume operations quickly after faults.
      • Lucidity: A clear and understandable system promotes efficient collaboration and easier maintenance.
      • Modifiability: Modular systems enable smooth changes without impacting other components.

    Fault Tolerance

    • Fault tolerance enables continuous operation despite failures through effective request rerouting and redundancy.
    • Replication: Clones services and data across multiple servers for safety and inherent data accessibility.
    • Checkpointing: Backups the system's state to restore it following data loss or corruption, employing synchronous or asynchronous methods for checkpoint creation.

    Fallacies of Distributed Computing

    • Reliable Network: Networks are often unstable; design for potential faults.
    • Zero Latency: Latency is unavoidable; optimize proximity to data through edge-computing and strategic server placement.
    • Infinite Bandwidth: Network resource contention leads to limits; use lightweight data formats and multiplexing to optimize bandwidth.
    • Secure Network: A network is not inherently secure; adopt a security-first approach and conduct thorough assessments.
    • Fixed Topology: Network topologies fluctuate continuously due to system changes; design must account for dynamism.### System Design Fallacies
    • Fixed topology assumptions can lead to issues such as latency and bandwidth problems; systems should be designed to be topology-agnostic.
    • The assumption of a "Single Administrator" fails in large-scale distributed systems due to multiple teams and OS; systems need decoupled designs for easier troubleshooting.
    • "Zero Transport Cost" is a fallacy; network infrastructure requires investment in hardwares, software, and teams, thus costs must be accounted in budgets.
    • Networks are not homogeneous; variations in device configurations and protocols necessitate an emphasis on interoperability among subsystems.

    AWS Well-Architected Framework

    • The framework consists of six core pillars designed to guide system design and mitigate common fallacies.
    • Pillars include:
      • Operational Excellence: Avoids issues related to Single Administrator and Homogeneous Network.
      • Security: Addresses the Secure Network fallacy.
      • Reliability: Counters Reliable Network and Fixed Topology fallacies.
      • Performance Efficiency: Tackles Zero Latency and Infinite Bandwidth assumptions.
      • Cost Optimization & Sustainability: Overcome the Zero Transport Cost assumption.

    System Design Trade-offs

    • Balancing cost, scalability, reliability, maintainability, and robustness is crucial when designing large-scale systems.
    • Performance trade-offs may require decisions between higher reliability with greater costs versus budget constraints impacting robustness and scalability.

    Time vs Space Trade-off

    • Time-memory trade-offs are essential; choosing between quick calculations using more memory or time-consuming recalculations must be respected in algorithm design.

    Latency vs Throughput

    • Latency is the time a request waits, while throughput measures actual data processed; these metrics have an inverse relationship, as increased latency reduces throughput.
    • Percentile metrics (e.g., p90 latency) gauge performance more effectively than average latency.

    Performance vs Scalability

    • Performance focuses on single request efficiency; scalability deals with system behavior under increased load; both aspects require careful management to meet user demands.

    Consistency vs Availability (CAP Theorem)

    • CAP Theorem states it's impossible to guarantee consistency, availability, and partition tolerance simultaneously in a distributed system.
    • Systems must prioritize either consistency or availability during network failures, emphasizing partition tolerance in designs.

    PACELC Theorem

    • PACELC expands on CAP, indicating the need to balance between availability and consistency during partitions and between latency and consistency otherwise.

    System Design Guidelines

    • Isolation: Develop modular systems for ease of maintenance, reusability, scalability, and reliability.
    • Simplicity: Employ KISS principles to build straightforward systems that focus on core requirements without unnecessary complexity.
    • Performance: Utilize metrics and observability as critical components to assess system performance and preempt issues.
    • Trade-offs: Recognize that optimizing one factor often affects others; value careful consideration in system design choices.
    • Use Cases: Understand that each design decision depends on specific user needs, constraints, and contextual factors, emphasizing custom solutions over one-size-fits-all approaches.

    Conclusion

    • Effective system design requires balancing competing factors and understanding the broader implications of decisions.
    • Future chapters will delve into foundational concepts related to data storage, caching, load balancing, and networking within system architecture.

    System Design Overview

    • Large-scale software systems are fundamental to modern technological advancements, evidenced by companies like Google, Amazon, Oracle, and SAP.
    • First principles thinking is critical in designing technical architecture to prevent issues later in the implementation process.

    Importance of System Design

    • Successful system design focuses on business requirements, customer needs, and various trade-offs to ensure long-term functionality.
    • Careful consideration of system bottlenecks and user access patterns is essential for effective system design.

    Foundational Concepts in System Design

    • Key concepts include:
      • Communication
      • Consistency
      • Availability
      • Reliability
      • Scalability
      • Fault tolerance
      • System maintainability

    Communication Mechanisms

    • Synchronous Communication:

      • Example: Real-time phone conversations where both parties communicate simultaneously.
      • The application waits for responses before proceeding, potentially causing perceived latency.

    • Asynchronous Communication:

      • Example: Email exchanges allowing delayed responses.
      • The sender does not wait for replies, facilitating flexibility and resilience in applications.

    Consistency in Systems

    • Consistency ensures all parts of a distributed system view data uniformly, pertinent in contexts like data storage and retrieval.
    • Consistency Techniques in distributed systems:
      • Data Replication: Multiple replicas are updated simultaneously for uniformity.
      • Consensus Protocols: Ensure agreement on data updates among nodes.
      • Conflict Resolution: Mechanisms to handle simultaneous conflicting updates from different replicas.

    Consistency in Data Storage

    • Techniques to maintain consistency in data storage include:
      • Write-ahead Logging: Logs write operations before application to data.
      • Locking Mechanisms: Control concurrent write access.
      • Data Versioning: Allows multiple concurrent writes while preserving read consistency.

    Consistency Spectrum Model

    • Consistency ranges from Eventual Consistency (leading to flexibility with potential data stale states) to Strong Consistency (ensuring all replicas are updated immediately after a write).

    Availability in Systems

    • Availability measures a system's capacity to serve requests effectively, even under failures.
    • Calculated as the proportion of uptime to total operational time, expressed as a percentage of the “nines” (e.g., 99.9999% represents six nines).

    Achieving High Availability

    • Each increment in availability comes with increased cost and complexity.
    • Techniques include:
      • Redundancy: Having backup components to maintain function amid failures.
      • Fault Tolerance: System resilience against unpredictable errors.

    System Arrangement Impacting Availability

    • Sequential Systems: The overall availability is multiplied across components; e.g., two 99.9% components yield 99.8% availability.
    • Parallel Systems: Availability is significantly improved as components can serve requests simultaneously, leading to a maintained uptime (e.g., two 99.9% components yield 99.9999% availability).

    Ensuring System Availability

    • Critical for maintaining performance and reliability through methods like redundancy and fault tolerance to navigate failure scenarios effectively.### Availability Mechanisms
    • Systems can achieve high availability through error-handling mechanisms, redundant hardware, or self-healing systems.
    • Load balancing distributes incoming requests across multiple servers to efficiently manage heavy loads and enhance availability.
    • Active-active and active-passive are the two primary failover patterns utilized to maintain system availability.

    Failover Patterns

    • Active-active failover: Multiple systems process requests in parallel; if one fails, others continue operations, providing flexibility but increasing complexity.
    • Active-passive failover: One primary system handles requests while passive backups wait to take over if the primary fails. This method is simpler but can cause delays during failover, reducing availability.

    Replication Patterns

    • Replication maintains multiple data copies to enhance availability and fault tolerance, with multi-leader and single-leader formats being the two main types.
    • Multi-leader replication: Multiple systems can read and write data, offering flexibility but increasing complexity and potential latency due to conflict resolution.
    • Single-leader replication: A single leader manages commands while followers replicate data for read operations only. This approach risks data loss if the leader fails and can lead to replication lag.

    Reliability Measurement

    • Reliability reflects a system's consistency in performing intended functions. Key metrics include:
      • Mean Time Between Failures (MTBF): Time a system operates without failure; higher is more reliable.
      • Mean Time to Repair (MTTR): Time to restore a system after failure; lower is better.

    Reliability vs. Availability

    • Reliability and availability are interrelated; a reliable but unavailable system fails at critical times, while an available but unreliable system may perform erratically.
    • Meeting service level objectives (SLOs) requires incorporating redundancy and failover mechanisms alongside regular maintenance.

    Scalability

    • Scalability ensures system performance improves with additional resources in response to increased workloads, whether from user requests or data storage needs.
    • Vertical scaling enhances a single server's capabilities but has limits and high costs associated with resource upgrades.
    • Horizontal scaling involves adding multiple servers, providing cost-effective scalability for variable traffic levels but adds management complexity.

    Maintainability

    • Maintainability allows a system to adapt to changing user needs without disrupting operations. Three key aspects include:
      • Operability: The system should function smoothly and resume operations quickly after faults.
      • Lucidity: A clear and understandable system promotes efficient collaboration and easier maintenance.
      • Modifiability: Modular systems enable smooth changes without impacting other components.

    Fault Tolerance

    • Fault tolerance enables continuous operation despite failures through effective request rerouting and redundancy.
    • Replication: Clones services and data across multiple servers for safety and inherent data accessibility.
    • Checkpointing: Backups the system's state to restore it following data loss or corruption, employing synchronous or asynchronous methods for checkpoint creation.

    Fallacies of Distributed Computing

    • Reliable Network: Networks are often unstable; design for potential faults.
    • Zero Latency: Latency is unavoidable; optimize proximity to data through edge-computing and strategic server placement.
    • Infinite Bandwidth: Network resource contention leads to limits; use lightweight data formats and multiplexing to optimize bandwidth.
    • Secure Network: A network is not inherently secure; adopt a security-first approach and conduct thorough assessments.
    • Fixed Topology: Network topologies fluctuate continuously due to system changes; design must account for dynamism.### Fallacies in System Design
    • Fixed topology assumptions lead to system issues due to latency and bandwidth constraints; systems must be agnostic to underlying topology.
    • The “Single Administrator” fallacy fails in large distributed systems; design should be decoupled for easier repair and troubleshooting given multiple teams and OSs.
    • The notion of “Zero Transport Cost” overlooks network infrastructure expenses, necessitating budget considerations for servers, switches, and maintenance teams.
    • Networks are heterogeneous, contrary to the “Homogeneous Network” fallacy; interoperability is essential for systems to function across diverse devices and protocols.

    AWS Well-Architected Framework

    • Comprises six core pillars for designing robust AWS systems:
      • Operational Excellence: Addresses the fallacies of Single Administrator and Homogeneous Network.
      • Security: Tackles the assumption of a Secure Network.
      • Reliability: Mitigates Fixed Topology and Reliable Network assumptions.
      • Performance Efficiency: Resolves issues related to Zero Latency and Infinite Bandwidth.
      • Cost Optimization and Sustainability: Counteracts Zero Transport Cost misconceptions.

    System Design Trade-offs

    • System design necessitates balancing cost, scalability, reliability, maintainability, and robustness to meet user needs.
    • Performance and scalability must be weighed; reliable systems may require expensive components for future scalability.
    • The Time vs Space trade-off arises when algorithmic performance is optimized using additional memory or storage.
    • Latency vs Throughput: As system load increases, latency metrics decline when aiming for higher throughput. Throughput measures actual data transmission, whereas bandwidth indicates potential limits.
    • Performance vs Scalability: A scalable system improves performance proportionally with additional resources, but may encounter latency under heavy user demand.
    • Consistency vs Availability: The CAP theorem states a distributed system cannot ensure consistency, availability, and partition tolerance simultaneously; typically, two of these are prioritized when faced with network partitions.

    CAP and PACELC Theorems

    • CAP Theorem: In distributed systems, one must choose between consistency and availability during network partitions.
    • PACELC Theorem: Extends CAP by indicating that in absence of network partition, trade-offs exist between latency and consistency.

    System Design Guidelines

    • Isolation: Modular systems enhance maintainability, reusability, scalability, and reliability by breaking down complexity into independent components.
    • Simplicity: KISS principle focuses on minimizing complexities and unnecessary features. Prioritize core requirements and avoid over-engineering.
    • Performance Metrics: Metrics and observability are critical; they provide baseline measurements for assessing system performance and identifying issues.
    • Trade-offs: Recognize that all design decisions involve trade-offs; optimizing one aspect often compromises another.
    • Use Cases: Emphasize that design depends on specific factors, and there is no universal approach in system design solutions.

    Conclusion

    • Effective system design requires balancing various trade-offs, understanding fallacies, and following established guidelines.
    • Next chapters will delve into fundamental aspects of systems, such as data storage, caching, load balancing, and communication networks.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Test your understanding of chapter 1 on System Design Trade-offs and Guidelines. This chapter dives into the foundational concepts and considerations essential for effective system design. Engage with the content and share your feedback for improvement!

    More Quizzes Like This

    Software Engineering: Transition from Requirements to Design Quiz
    20 questions

    Software Engineering: Transition from Requirements to Design Quiz

    MagicalAcademicArt avatar
    MagicalAcademicArt
    Génie Logiciel Chapter 1
    48 questions

    Génie Logiciel Chapter 1

    DaringVerdelite avatar
    DaringVerdelite
    WHO Dimension in System Design
    36 questions

    WHO Dimension in System Design

    TranquilAlliteration avatar
    TranquilAlliteration
    System Function Identification and Specification
    10 questions

    System Function Identification and Specification

    ReceptiveGiant7637 avatar
    ReceptiveGiant7637
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser