Network Architecture (PDF)

INTERNATIONAL & ACCESS FOUNDATION PROGRAMMES COMPUTER SCIENCE MODULE Semester I Part 6 Networks: PC Internals, Storage, and Network Storage © Dr Nevan Bermingham storage… Lets looks at a PC Structure to unde...

INTERNATIONAL & ACCESS FOUNDATION PROGRAMMES COMPUTER SCIENCE MODULE Semester I Part 6 Networks: PC Internals, Storage, and Network Storage © Dr Nevan Bermingham storage… Lets looks at a PC Structure to understand the hardware. This is the model of a computer: Inside a PC… A Motherboard What is RAM? DDR is RAM  Random Access Memory RAM is basically computer data storage for programs currently in use. When you click on a program icon, the program loads onto RAM after which you can use it. Most RAM chips wipe their memory once the computer is powered off (volatile memory), hence you always need to load your programs from storage. What is DDR SDRAM? The DDR is a form of SDRAM. DDR SDRAM stands for Double Data Rate Synchronous Dynamic Random-Access Memory. DDR SDRAM has seen a number of iterations since the year 2000 when the first DDR was released. DDR 5 data transfer rates of between 3200 to 6400 Mbps with capacities ranging between 8 to 32GB.  ALU (Combinational logic Unit): Arithmetic Logic Unit is used for calculations Registers (Internal Memory) are small memory stores in the CPU used to temporarily store data (loaded from the data bus) during processing. Bus is used to transfer information to and from main memory and other peripherals. Data Bus: For data transfer Address Bus: to select the location of the data Control Bus: dictates the control (timing) of the transfer Power Bus: delivers power to the computer components Control unit: controls the operations of all parts of the computer but does not carry out any actual data processing operations and handles with instructions from memory. Cache (see next page)  Chipset is a set of electronic components in one or more integrated circuits that manages the data flow between the processor, memory and peripherals. It is usually found on the motherboard. Chipsets are usually designed to work with a specific family of microprocessors. Because it controls communications between the processor and external devices, the chipset plays a crucial role in determining system performance. Memory Addressing In x86 Architecture A 32-bit system can access 232 different memory addresses, i.e 4 GB of RAM A 64-bit system can access 264 different memory addresses, i.e actually 18- Quintillion bytes of RAM (18 Exabytes). It can easily handle 32GB or 64GB of memory. A major difference between 32-bit processors and 64-bit processors is the number of calculations per second they can perform, which affects the speed at which they can complete tasks. Multiple cores allow for an increased number of calculations per second that can be performed 64-bit architecture needs an Operating System that is 64-bit. Paging Giving the System more memory than it physically has Swap-file (Paging) Swap is a Virtual RAM which acts as a RAM but uses the secondary storage to save data. With swap, a small portion of the hard drive is set aside and used like RAM. The computer will attempt to keep as much information as possible in RAM until the RAM is full. At that point, the computer starts moving inactive blocks of memory that are paged to the hard disk, freeing up RAM for active processes. If one of the pages on the hard disk needs to be accessed again, it will be moved back into RAM, and a different inactive page in RAM will be moved onto the hard disk (swapped). A CPU Cache CPU L1 RAM Cache A CPU cache is a small Memory memory location within Registers the CPU itself used by On-chip the CPU of a computer to reduce the average time to access data from the main memory. A cache will store recent data. A CPU Cache Levels  When the processor needs to read from or write to a location in main memory, it first checks whether a copy of that data is in the cache.  If so, the processor immediately reads from or writes to the cache, which is much faster than reading from or writing to main memory  Cache’s are faster then accessing memory, but may not always “prefetch” or hold the data the CPU needs.  An issue with speed versus accuracy is the fundamental tradeoff between cache latency and hit rate.  Larger caches have better hit rates but longer latency.  To address this tradeoff, many computers use multiple levels of cache, with small fast caches backed up by larger, slower caches.  Multi-level caches generally operate by checking the fastest, level 1 (L1) cache first; if it hits, the processor proceeds at high speed. GP U  Stands for Power On Self Test OR Pre-Operating System Test https://www.opennaukri.com/what-is-bios-and-its-functions/ Read the detail here… Read this website: https://www.partitionwizard.com/partitionmanager/motherboard-components. html And Read the detail in this PDF file. Parts of Motherboard and its Function Explained.pdf Now, lets look at storage… Types of Disk Storage Mechanical ‘Hard’ Disk Drives (e.g. ATA IDE Drives, SCSI Drives) Solid State Disks (SSD) – SATA, but now usually PCIe 3.0 or M.2 SSD Form Flash Drives (e.g. USB Key) Kingston ‘LSI Tape (Mostly obsolete now)SandForce’ M.2 SSD Optical Drives (CD, DVD) Intel ePCI SSD Mechanical ‘Hard’ Disk Drives Mechanical ‘Hard’ Disk Drives Stores data using magnetic polarity ‘Hard’ Disk Drives Size Growth ‘Hard’ Disk Drives Size Growth Hard Drives Data Solid State Disk HDD & SSD Internal Architecture Solid State Disk SSD HDD Access time An SSD has access speeds of 35 to A typical HDD takes about 5,000 to 100 micro-seconds, which is nearly 10,000 micro-seconds to access 100 times faster. This faster access data. speed means programs can run more quickly, which is very significant, especially for programs that access large amounts of data often like your operating system. Price The price of a solid state drive is HDD is much cheaper than SSD, much more than an HDD especially for drives over 500GB. Reliability The SSD drive has no moving parts. The HDD has moving parts and It uses flash memory to store data, magnetic platters meaning the more which provides better performance use they get, the faster they wear and reliability over an HDD. down and fail. Power The SSD uses less power than a With all the parts and requirements standard HDD, which means a lower to spin the platters the HDD uses energy bill over time and for laptops more power than an SSD. an increase of battery life. Noise With no moving parts SSD generates With the spinning platters and no noise. moving read/write heads an HDD can sometimes be one of the loudest components in your computer. Optical Storage Making Disk Storage Reliable If a Hard Drive fails, you lose all that data. An option is to backup regularly, but: Critical Real time data cannot easily be retrieved from backups Backups take time to create and restore (downtime) Solution is to use an array of disks in a format called RAID (Redundant Arrays of Independent Disks) RAID Levels RAID Explained RAID Level 0 “Stripping Data” RAID Level 1 “Mirror Data” RAID Level 10 = “Mirror Data” AND “Stripping Data” => Most expensive, but safer and better performance. Real World RAID Arrays RAID Array in a Server Rack Unit Example of a Rack Server (1U) - Lenovo System x3250 M6 Rack servers are typically built with all the needed components to operate as a stand-alone system. Example of a Rack Server (1U) - Lenovo System x3250 M6 Blade Severs A blade server is a stripped-down server computer with a modular design optimized to minimize the use of physical space Blade servers are generally used when there is a high computing requirement with some type of Enterprise Storage System: Network Attached Storage (NAS) or a Storage Area Network (SAN). They maximize available space by providing the more processor density. Blade Servers also allow hot-swapping (swapped out without taking the machine offline) Each blade contains a single server, often dedicated to a single application (stored on a memory RAM) Blade servers function well for specific purposes such as web hosting, virtualization, and cluster computing. File Systems FAT and NTFS is nothing but just the method to organize the data in the File System Format. FAT and NTFS both support the partition tables for the storage of data. NTFS is standard file system Microsoft, which is starting with Windows NT 3.1 NTFS is supported in other desktop and Operating system like Linux, BSD (UNIX) and free and open sources. Mac OS support NTFS file System but only in readable mode. NTFS prevents accessing of file disk data without mentioning the username and password, hence makes it more secured.  Group Task: Research how FAT works. One Minute to Present your findings Disk FAT File Allocation Tables Disk FAT File Allocation Tables Ideal World The computer will attempt contiguous allocation. But over time files become “fragmented” Disk FAT File Allocation Tables Actual FAT Disk FAT File Allocation Tables Actual FAT Location #1 End of File (Last Block) Location #5 Start of File (First Block) Location #12 Middle Block 2 of 3 NAS (Network Attached Storage) NAS – Shared Network Storage Clients Common Internet File Systems (CIFS) for Windows Clients Network File Systems (NFS) for UNIX Clients Type of Application Print Disk Server Server Storage Drives NAS A network-attached storage (NAS) device is a server that is dedicated to file sharing. NAS does not provide any of the activities that a server in a server-centric system (client server) typically provides, such as e-mail, authentication or file management. NAS allows more hard disk storage space to be added to a network without shutting them down for maintenance and upgrades (“hot upgrading”) NAS With a NAS device, storage is not an integral part of the server. Instead, in this storage-centric design, the server still handles all of the processing of data but a NAS device delivers the data to the user. A NAS device does not need to be located within the server but can exist anywhere in a LAN and can be made up of multiple networked NAS devices. Why NAS?  Improves efficiency  Provides flexibility  Centralizes storage  Simplifies management  Scalability  High availability  Provides security integration to environment (user authentication and authorisation) Drive for NAS THE PAST TODAY Critical Business Outside the Applications Data Center (Databases) Islands of Integrated Information Infrastructure Tools and Enterprise Scripts Management What a NAS looks like… NAS Advantages & Properties Performance: includes physical device performance (CPU utilization, memory utilization, number of I/O requests received, cache performance) as well as CIFS/NFS performance. Management software should not only collect this data, but also filter it so intelligent events can be initiated when thresholds are breached. Discovery: the ability to discover a NAS device(s) – along with its hardware configuration and logical storage attributes—as they change, without manual entry. Space Management: administrators need to know who is using it, what they are using, and how much of it. Backup/Recovery: Automatic and Reliable  Storage Area Networks (SAN) A SAN, or Storage Area Network, is similar to NAS, but instead of being on the network, a SAN is generally on it’s OWN network. SANS tend to be much larger scale than NAS solutions. By utilising its own network to interconnect storage related resources, it avoids clogging the primary network. Storage Area Networks (SAN) Storage (data store) is separated from the processors (and separated processing). High capacity, high availability, high scalability, ease of configuration, ease of reconfiguration. Fiber Channel is the de facto SAN networking architecture, although other network standards could be used. SAN Architecture Primary LAN Servers Fiber Channel Switch (Dedicated High Speed Network with Redundancy) Clients Disk Array & SAN Controller SAN Architecture What it looks like. SAN Architecture HP StoreOnce 4700 San Array Capacity : 24TB Raw 20TB Useable Expandable to 192 TB Raw / 160 TB Useable Drive description : (12) LFF SAS Supported Drive type (12) 2 TB 6G 7.2K LFF Dual-port MDL SAS RAID Disk Arrays Included : Host interface 8 Gb/sec Fibre Channel (4) and 10 GbE (2) & 1Gb Ethernet (4) SAN Traditionally: NAS is used for low-volume access to a large amount of storage by many users SAN is the solution for terabytes of storage and multiple, simultaneous access to files, such as streaming audio/video, or large high speed real-time databases. SAN Storage consolidation Data sharing Non-disruptive scalability for growth Improved backup and recovery LAN-free and server-free data movement (its own network backbone or “Host Bus”) High performance High availability High data integrity Disaster tolerant  Cloud Computing Cloud Computing is a general term used to describe a new class of network based computing that takes place over the Internet, Its a collection/group of integrated and networked hardware, software and Internet infrastructure (called a platform). Using the Internet for communication and transport provides hardware, software and networking services to clients These platforms hide the complexity and details of the underlying infrastructure from users and applications by providing very simple graphical interface or API (Applications Programming  Cloud Computing A number of characteristics define cloud data, applications services and infrastructure: Remotely hosted: Services or data are hosted on remote infrastructure. Ubiquitous: Services or data are available from anywhere. Commoditised: The result is a utility computing model similar to traditional that of traditional utilities, like gas and electricity - you only pay for what you would use. The “Cloud” SaaS & Could Computing  Simply put, cloud computing is the delivery of computing services—servers, storage, databases, networking, software, analytics and more—over the Internet (“the cloud”).  Companies offering these computing services are called cloud providers and typically charge for cloud computing services based on usage, similar to how you are billed for water or electricity at home.  Software-as-a-service (SaaS) is a method for delivering software applications over the Internet, on demand and typically on a subscription basis.  With SaaS, cloud providers host and manage the software application and underlying infrastructure and handle any maintenance, like software upgrades and security patching.  Users connect to the application over the Internet, usually with a web browser on their phone, tablet or PC. Software as a Service (SaaS) Software as a Service (SaaS) Common Characteristics: Massive Scale Resilient Computing Homogeneity Geographic Distribution Virtualization Service Orientation Low Cost Software Advanced Security Essential Characteristics: On Demand Self-Service Broad Network Access Rapid Elasticity Resource Pooling Measured Service SaaS service Layers Services Description Services – Complete business services such as PayPal, OpenID, OAuth, Services Google Maps, Alexa Application – Cloud based software that eliminates the need for local Application Application installation such as Google Apps, Microsoft Online Focused Development – Software development platforms used to build custom Development cloud based applications (PAAS & SAAS) such as SalesForce Platform – Cloud based platforms, typically provided using Platform virtualization, such as Amazon ECC, Sun Grid Storage – Data storage or cloud based NAS such as CTERA, iDisk , Infrastructure Storage CloudNAS Focused Hosting – Physical data centers such as those run by IBM, HP, Hosting NaviSite, etc. Cloud Delivery Models Explained Saas & PaaS Advantages It enables services to be used without any understanding of their infrastructure. Cloud computing works using economies of scale: It potentially lowers the outlay expense for start up companies, as they would no longer need to buy their own software or servers. Cost would be by on-demand pricing. Vendors and Service providers claim costs by establishing an ongoing revenue stream. Data and services are stored remotely but accessible from “anywhere”. Advantages Improved performance:  With fewer programs on your computer's memory, you will see better performance from your PC.  Computers in a cloud computing system boot and run faster because they have fewer programs and processes loaded into memory. Reduced software costs:  Most cloud computing applications today are free, such as the Google Docs suite.  Cheaper than paying for similar commercial software Instant software updates Unlimited storage capacity Challenges Security? Easier to hack your account. The legal system of the country your data is stored? Market dominance of big companies Google and IBM. Trusting your data to someone else. Internet Access required. Speed of Internet Access. Cloud Storage Several large Web companies are now exploiting the fact that they have data storage capacity that can be hired out to others. Allows data stored remotely to be temporarily cached on desktop computers, mobile phones or other Internet-linked devices. Pay for what you use. Available everywhere there is internet. Backups and Data Security managed by the provider. Task: Network Storage With the person next to you think about the following: If you were deploying a network storage solution, what questions would you ask before suggesting a solution? Agree and pick your top three questions. Any Questions?