CompTIA Chapter 8: Power Supplies & Storage Technologies PDF

Chapter 8 Power Supplies **How Hard Drives Work** **HDD (hard disk drive):** is composed of individual disks, or platters, with read/write heads on actuator arms controlled by a servo motor---all contained in a sealed case that prevents contamination by outside air. The aluminum platters are coat...

Chapter 8 Power Supplies **How Hard Drives Work** **HDD (hard disk drive):** is composed of individual disks, or platters, with read/write heads on actuator arms controlled by a servo motor---all contained in a sealed case that prevents contamination by outside air. The aluminum platters are coated with a magnetic medium. Two tiny read/write heads service each platter, one to read/write on top of the platter and the other to read/write on the bottom of the platter. Each head has a bit-sized transducer to read or write to each spot on the drive. Many folks refer to traditional HDDs as **magnetic hard drives, spinning drives, spindles, mechanical drives, or sometimes spinning rust.** **Spindle (or Rotational) Speed** Hard drives have spindle speeds measured in RPM, revolutions per minute, with common speeds being 5400 and 7200 RPM, and high-performance drives at 10,000 or 15,000 RPM. Faster speeds improve performance but increase noise and heat, which can significantly shorten a drive\'s lifespan. The form factor only defines size, while internal connections and technology vary. Traditional drives contribute to longer boot times due to their need to spin up before accessing data. **Solid-State Drives** Solid-state technology and devices are based on the combination of semiconductors and transistors used to create electrical components with no moving parts. **SSDs for personal computers come in one of three form factors:** - 2.5-inch form factor previously. - two flat form factors called: - mSATA and M.2 drives connect to specific mSATA or M.2 slots on motherboards. Many current motherboards offer two or more M.2 slots. M.2 slots come in various configurations, keyed for specific uses. M.2 SSDs also vary in size, identified by a number where the first two digits indicate the width in millimeters and the remaining digits the length. **Here\'s a breakdown of the key information regarding M.2 slots and SSDs:** 1\. **Keying:** \- **Key B:** Typically used for SATA or PCIe x2 lanes (two lanes), often found in SSDs. \- **Key [M:]** [Used for PCIe x4 lanes (four lanes),] commonly seen in Nonvolatile Memory Express NVMeSSDs for faster data transfer rates that connect to the motherboard to send data between the drive and the CPU. \- **Key B+M**: Combines both B and M, providing compatibility with either key type. It can support both SATA and PCIe x2 connections. \- **Key A** and **Key E**: Used mainly for wireless networking cards, such as Wi-Fi and Bluetooth modules. 2\. **M.2 SSD Sizes**: \- The size coding of M.2 SSDs conveys both the width and length: \- \_\_\_\_\_\_:22 mm wide and 30 mm long. \- **2242:** 22 mm wide and 42 mm long. \- **2260**: 22 mm wide and 60 mm long. \- 2**280**: 22 mm wide and 80 mm long, this is the most common size for consumer SSDs. \- **22110**: 22 mm wide and 120 mm long. Length affects the overall storage capacity, with longer SSDs able to house more NAND flash chips, thereby offering larger storage capacities. 3\. **Data Storage Technology**: \- M.2 SSDs use nonvolatile flash memory, specifically NAND, which retains stored data even when the power is turned off. This technology allows for fast data access and is vital for maintaining the integrity of saved information.  **SATA (Serial ATA)** is an interface used to connect storage devices like hard drives and SSDs to the motherboard. Here are some key points about SATA compared to its predecessor, PATA (Parallel ATA): **1. Point-to-Point Connection:** **-** SATA creates a direct connection between the storage device and the SATA controller, which is typically part of the host bus adapter (HBA). This setup contrasts with PATA\'s shared bus architecture, where multiple devices could be attached to the same ribbon cable. **2. Physical Differences:** \- SATA devices have noticeably different connectors compar5d to PATA. They use a 7-pin data connector and a 15-pin power connector, which are much smaller and more efficient than PATA\'s 40-pin ribbon cables and larger Molex power connectors. **3. Serial vs. Parallel Data Transfer:** \- SATA transmits data serially, meaning data travels one bit at a time, whereas PATA transmitted data in parallel, sending a byte or more simultaneously over multiple wires. This serial data transmission allows SATA to utilize fewer wires, resulting in a much thinner, more manageable cabling system. **4. Advantages of Thinner Cables:** \- The thin SATA cables improve internal airflow within the PC case, which helps with cooling by reducing air resistance and obstruction. This is particularly important in maintaining optimal operating temperatures for components. **5. Cable Length:** **-** SATA cables can be up to about 1 meter (40 inches) long, more than twice the maximum cable length of PATA cables, which were limited to 18 inches. This increased length makes it easier to install drives in larger cases or specific configurations without worrying about cable reach. Solid-state drives operate internally by writing data in a scattershot fashion to highspeed flash memory cells in accordance with the rules contained in the internal SSD controller. That process is hidden from the operating system by presenting an electronic façade to the OS that makes the SSD appear to be a traditional magnetic hard drive. **Performance Variables** **When buying an SSD, there are three key performance metrics to consider:** 1\. **Sequential Read/Write Performance**: This measures the drive\'s top speed for reading and writing long sequences of data, typically indicating throughput. Drives generally read faster than they write. 2\. **Random Read/Write Performance:** This assesses how many times per second the drive can read or write small, fixed-size data chunks (often 4 KB) at random locations. These metrics, often labeled as 4K Read or 4K Write, are expressed in input/output operations per second (IOPS) or sometimes in MBps. 3\. **Latency:** This measures the drive\'s response or access time, indicating how quickly it handles a single request. Lower latency is crucial for high-performance tasks, though most modern drives offer sufficient latency for general use, making them acceptable for typical applications. **Hybrid Drives** The combination of a conventional magnetic hard drive and a substantial amount of solid state storage. This combination is to improve access speed for frequently accessed data while yet providing larger capacity comparable to a normal HDD. Some hybrid SSDs, are not hot-swappable and they typically larger that USB and SD drives. **S.M.A.R.T (Self-Monitoring, Analysis, and Reporting Technology**): was introduced by TA/ATAPI version 3, an internal drive program that tracks errors and error conditions within the drive. This information is stored in nonvolatile memory on the drive and can be examined externally with S.M.A.R.T. reader software. There are generic S.M.A.R.T. reading programs, and every drive manufacturer has software to get at the vendor specific information being tracked. Regular usage of S.M.A.R.T. software will help you create a baseline of hard drive functionality to predict potential drive failures. **SATA** This passage explains some key differences between SATA (Serial ATA) and PATA (Parallel ATA) interfaces, highlighting the advantages of SATA. Here are the main points: 1\. **Connection Type**: SATA creates a point-to-point connection between the device (like hard drives or optical drives) and the controller, known as the host bus adapter (HBA). 2\. **Cable and Connector Differences**: \- SATA uses a 7-wire connector compared to the 40-wire connectors in PATA, due to its serial data transmission. \- This results in thinner cables, which improve cable management and airflow in the PC case, enhancing cooling. 3\. **Cable Length**: \- SATA cables can be up to 40 inches (1 meter) long, which is more than twice as long as the maximum length of a PATA cable (18 inches). \- This allows for easier drive installation in larger computer cases. For the last 25+ years, the Storage Networking Industry Association's Small Form Factor (SFF) committee has defined mass storage standards, the most important to CompTIA A+ techs being ATA/ATAPI. **NOTE** Check out the Storage Networking Industry Association's Web site (https://www.snia.org) for a good source for mass storage standards. **PATA** PATA drives are easily recognized by their data and power connections. PATA drives used unique 40-pin ribbon cables. These ribbon cables usually plugged directly into a system's motherboard. **Integrated Drive Electronics (IDE)** is a standard interface for connecting data storage devices, particularly hard drives and optical drives, to a computer\'s motherboard. It simplifies the connection by integrating the controller directly into the drive itself, eliminating the need for a separate interface card. This makes installation and configuration easier. **Here are some key points about IDE:** 1\. **Connection and Configuration:** IDE typically uses a 40-pin ribbon cable to connect the drive to the motherboard. Drives can be set up as Master or Slave, allowing multiple drives on a single cable. 2\. **Transfer Speeds:** IDE interfaces have evolved over time, with different standards emerging. Early versions supported speeds of up to 16.6 MB/s (IDE/ATA-1), while later versions, such as Ultra ATA/133, increased this to 133 MB/s. 3\. **Common Usage**: IDE was widely used in personal computers during the 1990s and early 2000s for connecting hard drives and CD/DVD drives. However, it has largely been replaced by the Serial ATA (SATA) interface, which offers faster speeds and more efficient data transfer. 4\. **Limitations:** While IDE supports multiple devices on a single bus, it has limitations in speed and cabling flexibility compared to SATA. The size and bulk of IDE cables can also restrict airflow in computer cases. 5\. **Legacy Status**: Today, IDE is considered a legacy interface. Most modern systems utilize SATA or other technologies like NVMe (Non-Volatile Memory Express) for solid-state drives (SSDs), which provide significantly higher data transfer rates. IDE played a crucial role in the evolution of computer storage technology, helping to standardize how drives connected to motherboards, paving the way for newer advancements in data storage interfaces.  Each drive connects to one port. Further, there's no maximum number of drives---many motherboards today support up to eight SATA drives, Snap in a SATA HBA into an expansion slot and load 'em up with even more drives. The biggest news about SATA is in data throughput. SATA devices transfer data in serial bursts instead of parallel, as PATA devices do. A SATA device's single stream of data moves much faster than the multiple streams of data coming from a parallel ATA device. faster. **SATA drives come in three common SATA-specific varieties:** SATA 1.0: 1.5 Gbps/150 MBps. SATA 2.0: 3 Gbps/300 MBps. SATA 3.0: 6 Gbps/600 MBps. SATA 3.2: up to 16 Gbps/2000 MBps. It should be noted that if a system has an (external) eSATA port (discussed next), it will operate at the same revision and speed as the internal SATA ports. Traditionally you do not connect or disconnect mass storage devices to a running system. Connecting a mass storage device to a fully functioning and powered-up computer may result in less-than-optimal results. The result may be as simple as the component not being recognized or as dire as a destroyed component or computer. **Hot-swapping entails two elements:** - First being the capacity to plug a device into the computer without harming either. - Second is that once the device is safely attached, it will be automatically recognized. and become a fully functional component of the system. - SATA was the first popular mass storage technology to support hot swapping. - SATA Express (SATAe) ties capable drives directly into the PCI Express bus on otherboards. - SATAe drops both the SATA link and transport layers, embracing the full performance of PCIe. - The lack of overhead greatly enhances the speed of SATA throughput, with each lane of PCIe 3.0 capable of handling up to 8 Gbps of data throughput. - A drive grabbing two lanes,could move a whopping 16 Gbps through the bus. Without the overhead of earlier SATA versions, this translates as 2000 MBps! SATAe (also known as SATA 3.2) has unique connectors but provides full backward compatibility with earlier versions of SATA. Connects compatible drives to the PCIe bus on the motherboard, reducing overhead and taking advantage of PCIe bus speeds, which increase data throughput multiple times. **eSATA and Other External Drives** **eSATA (External SATA):** extended the SATA bus to external devices. The eSATA drives used connectors that looked similar to internal SATA connectors, but were keyed differently so you couldn't mistake one for the other. External SATA used shielded cable in lengths up to 2 meters outside the PC and was hot-swappable. eSATA extended the SATA bus at full speed, mildly faster than the fastest USB connection when it was introduced. Current external enclosures (the name used to describe the casing of external HDDs and SSDs) use the USB (3.0, 3.1, 3.2, or C-type) ports or Thunderbolt ports for connecting external hard drives. The drives inside the enclosures are standard SATA HDDs or SSDs. Here\'s a summary of USB cable length recommendations and options for extending USB connections: **USB Cable Length Recommendations:** - **USB 1.0:** - Supports 12 Mbps. - Recommended length: 3 meters (9.8 feet). - **USB 2.0:** - Supports 480 Mbps. - Maximum recommended length: 5 meters. - **USB 3.0:** - Supports 5 Gbps. - Recommended length: Up to 3 meters (9.8 feet). - **USB 3.1 (Gen 2):** - Supports 10 Gbps. - Recommended length: 3 meters (9.8 feet). - **USB4:** - Recommended length: Up to 0.8 meters. Extending USB Connections: - **USB Hub:** - Used to extend the reach of USB connections by adding more ports, often with additional power support. - **Active USB Cable:** - Contains built-in electronics to amplify the signal over longer distances and may have external power sources or additional USB A connectors for power. - **Cat 5/Cat 6 USB Extender:** - Converts USB signals for transmission over Ethernet cables, allowing for significantly longer distances. **Ethernet Cable Categories:** 1. **Cat 3:** - **Max Speed:** 10 Mbps. - **Bandwidth:** 16 MHz. - **Use Case:** Old telephone networks, early Ethernet (10Base-T). - **Max Length:** 100 meters (328 feet). 2. **Cat 5:** - **Max Speed:** 100 Mbps (can support 1 Gbps unofficially). - **Bandwidth:** 100 MHz. - **Use Case:** Fast Ethernet, legacy networks (largely obsolete). - **Max Length:** 100 meters (328 feet). 3. **Cat 5e (Enhanced):** - **Max Speed:** 1 Gbps. - **Bandwidth:** 100 MHz. - **Use Case:** Gigabit Ethernet. - **Max Length:** 100 meters (328 feet). 4. **Cat 6:** - **Max Speed:** 1 Gbps up to 55m, 10 Gbps up to 37-55m. - **Bandwidth:** 250 MHz. - **Use Case:** Gigabit Ethernet, short-run 10 Gigabit Ethernet. - **Max Length:** 100 meters (328 feet) for 1 Gbps; 55 meters (180 feet) for 10 Gbps. 5. **Cat 6a (Augmented):** - **Max Speed:** 10 Gbps. - **Bandwidth:** 500 MHz. - **Use Case:** 10 Gigabit Ethernet over longer distances. - **Max Length:** 100 meters (328 feet). 6. **Cat 7:** - **Max Speed:** 10 Gbps. - **Bandwidth:** 600 MHz. - **Use Case:** Specialized networking applications, not an IEEE standard, is not TIA/EIA approved and it does not use a regular RJ45 connector. - **Max Length:** 100 meters (328 feet). 7. **Cat 7a:** - **Max Speed:** 10 Gbps. - **Bandwidth:** 1,000 MHz. - **Use Case:** Higher bandwidth than Cat 7; less common. - **Max Length:** 100 meters (328 feet). 8. **Cat 8:** - **Max Speed:** 25 or 40 Gbps. - **Bandwidth:** 2,000 MHz. - **Use Case:** Data centers, short connections between high-speed storage and switches, is IEEE approved, can support 10Gbp over 100 meters and 40 GBps over extremely small distances (24 meters) making it suitable for storage area networks (SAN). - **Max Length:** 30 meters (98 feet). **EXAM TIP Know your cable lengths:** PATA (IDE): 18 inches. SATA: 1 meter. eSATA: 2 meter. **AHCI** Current versions of Windows support the **Advanced Host Controller Interface (AHCI),** an efficient way to work with SATA HBAs. **Using AHCI unlocks some of the advanced features of SATA:** - **NCQ (Native command queuing):** is a disk-optimization feature for SATA drives. It takes advantage of the SATA interface for faster read and write speeds than old PATA drives. - **Hot-swapping:** the motherboard and the operating system must also support this. AHCI mode is enabled at the CMOS level (see "BIOS Support: Configuring CMOS and Installing Drivers" later in this chapter) and generally needs to be enabled before you install the operating system. Enabling it after installation will cause Windows to Blue Screen. AHCI must be enabled to automatically detect when you plug in a SATA drive when you plug one in in when Windows is running. Otherwise, it won't by default. **Successfully Switching SATA Modes Without Reinstalling** You can attempt to switch to AHCI mode in Windows without reinstalling. This scenario might occur if a client has accidentally installed Windows in Legacy/IDE mode, for example, and finds that the new SSD he purchased requires AHCI mode to perform well. 1. Back up everything before attempting the switch. 2. You need to run through some steps in Windows before you change the BIOS/UEFI settings. Windows 10 and 11 use an elevated command prompt exercise with the bcdedit command. A quick Google search for "switch from ide to ahci windows" will reveal several excellent walkthroughs of the process for Windows 10 and 11. Back everything up first! **NVMe** AHCI (Advanced Host Controller Interface) was originally designed to optimize read performance and enable hot-swapping for spinning SATA drives. Although AHCI configuration can work with many SSDs, it is not ideal. This is because SSDs must include circuitry to appear as traditional spinning drives to the operating system, translating read and write operations through this virtual interface. The **NVMe (Non-Volatile Memory Express)** specification, on the other hand, allows SSDs to connect directly to the operating system via a PCIe bus lane. This approach reduces latency and fully utilizes the high-speed capabilities of modern SSDs, making it a more efficient choice for high-performance storage solutions. **NVMe SSDs come in a few formats**: - Add-on expansion card using a PCIe slot on the motherboard. - 2.5-inch drive that works with a SATAe connector. - The most common style, M.2 format. NVMe drives are more expensive than other SSDs but offer much higher speeds. **SCSI** **SCSI (small computer system interface):**rules the roost in the server market. SCSI devices---parallel and serial---use a standard SCSI command set, meaning you can have systems with both old and new devices connected and they can communicate with no problem. SCSI drives used a variety of ribbon cables, depending on the version. The 16-bitSCSI drives were connected using a Molex connector with tow rows of pins totaling 68 pins. **SAS (Serial Attached SCSI):** hard drives provide fast and robust storage for servers and storage arrays today. The latest SAS interface, SAS-4, provides speeds of up to 22.5 Gbps. SAS controllers also support SATA drives, offers a lot of flexibility for techs, especially in smaller server situations. SAS implementations offer more than a dozen different connector types. Most look like slightly chunkier versions of a SATA connector. A better solution, though, would save your data if a hard drive died and enable you to continue working throughout the process. This is possible if you stop relying on a single hard drive and instead use two or more drives to store your data. **Disk mirroring:** Disk Mirroring Disk mirroring is a data redundancy technique used to enhance data reliability and availability through the creation of an exact copy (or mirror) of a storage disk. Here's an overview of the key aspects of disk mirroring: **Key Concepts:** 1. **Redundancy:** - Disk mirroring involves duplicating data from one disk (the primary or source disk) to another disk (the mirror or target disk). This ensures that if one disk fails, the data remains accessible on the other disk. 2. **Real-Time Synchronization:** - Data is typically written to both disks simultaneously, ensuring that they hold identical information at any given time. This process is called synchronous write. 3. **Fault Tolerance:** - In the event of a hardware failure (e.g., a disk failure), the system can continue to operate using the mirrored disk, minimizing downtime and data loss. **Implementation:** - **Software vs. Hardware:** - Disk mirroring can be implemented using software (operating system features or third-party applications) or hardware (dedicated RAID controllers). - **RAID Configurations:** - Mirroring is commonly associated with RAID (Redundant Array of Independent Disks) configurations, particularly RAID 1. RAID 1 arrays consist of at least two disks that mirror each other. **Advantages:** 1. **Data Protection:** - Provides a safeguard against data loss due to hard drive failures. 2. **High Availability:** - Systems can remain operational even when one disk fails, allowing for continuous access to data. 3. **Simplified Recovery:** - Restoring data is straightforward, as it can be retrieved from the mirror rather than needing to restore from backup. **Disadvantages:** 1. **Cost:** - Requires double the disk space since all data is stored twice, making it more expensive in terms of storage hardware. 2. **Performance Impact:** - Writing data may be slightly slower, as it involves writing to two disks simultaneously, although read operations can benefit from improved performance. 3. **Not a Replacement for Backup:** - While mirroring protects against hardware failures, it does not safeguard against data corruption, accidental deletions, or disasters (e.g., fire, theft). Regular backups are still essential. **Disk duplexing:** Disk Duplexing Disk duplexing is a data protection technique similar to disk mirroring, but with an additional layer of fault tolerance by using separate disk controllers for each drive. Here's a detailed look at disk duplexing: **Key Concepts:** 1. **Redundancy:** - Like disk mirroring, disk duplexing involves creating an exact copy of data on two separate disks. This duplication ensures that data remains accessible if one disk fails. 2. **Separate Controllers:** - Each mirrored disk is connected to its own independent disk controller. This architecture enhances reliability by providing a safeguard not only against disk failures but also against controller failures. 3. **Fault Tolerance:** - With disk duplexing, the system can withstand the failure of both a disk and its controller, maintaining data availability and system uptime. **Implementation:** - **Hardware Setup:** - Typically requires two disk controllers, which can be onboard controllers or add-on cards, with each disk directly connected to a different controller. - **Synchronous Writing:** - Data is written to both disks at the same time via their respective controllers. Advantages: 1. **Enhanced Fault Tolerance:** - Provides greater protection than standard mirroring by including redundancy for controller failures in addition to disk failures. 2. **Higher Reliability:** - Reduces the risk of a single point of failure at both the disk and controller level, thus increasing overall system reliability. 3. **Continuous Operation:** - Ensures continued system operation without interruption, even if a disk or controller fails. **Disadvantages:** 1. **Increased Cost:** - Requires additional hardware, including an extra disk controller, increasing the overall cost of the system. 2. **Complexity:** - More complex to set up and maintain compared to simpler configurations like disk mirroring. 3. **Resource Utilization:** - Occupies more hardware resources and can be more challenging to configure correctly without specialized knowledge. **Disk striping:** Disk striping is a method used to improve the performance of storage systems by distributing data across multiple disks. Here's an overview of how disk striping works, its benefits, and its drawbacks: **Key Concepts:** 1. **Data Distribution:** - In disk striping, data is split into blocks and spread sequentially across multiple disks. Each disk stores a portion of the data, allowing read and write operations to be performed in parallel. 2. **Performance Enhancement:** - By leveraging multiple disks, striping can significantly improve data transfer rates and overall system performance, as operations can occur simultaneously across all disks. **Implementation:** - **RAID 0:** - Disk striping is commonly associated with RAID 0, where data is striped across two or more disks without providing any redundancy. RAID 0 is focused exclusively on performance enhancement. - **Block Size:** - The size of each striped block (or stripe size) can be configured to optimize performance for specific types of workloads or applications. **Advantages:** 1. **Increased Throughput:** - By splitting data across multiple disks, striping allows for faster data access, particularly beneficial in applications requiring high bandwidth, such as video editing or large database operations. 2. **Efficient Utilization:** - Maximizes the combined storage capacity of the disks used, as there is no overhead for redundancy. **Disadvantages:** 1. **Lack of Redundancy:** - RAID 0 provides no data protection. If any disk in the stripe set fails, all data in the array is lost because each disk holds only part of the complete dataset. 2. **Risk of Data Loss:** - The chance of data loss increases with more disks, as the failure risk is linked to the total number of disks in the array. **Disk Striping with Parity** Disk striping with parity combines the performance benefits of disk striping with data protection through parity. This method is commonly used in RAID 5 (and RAID 6), providing both speed improvements and fault tolerance. Here\'s a detailed look at how it works: **Key Concepts:** 1. **Data Striping:** - Similar to standard disk striping, data is divided into blocks and distributed across multiple disks to enhance performance by allowing parallel read and write operations. 2. **Parity:** - A parity block is calculated for each set of data blocks and is stored across the disks in the array. The parity information is used to reconstruct data in the event of a disk failure. 3. **Fault Tolerance:** - By using parity, the array can recover data if one disk fails (RAID 5) or up to two disks fail (RAID 6). **Implementation:** - **RAID 5:** - Requires at least three disks. Data and parity are striped across all disks. The parity information allows data recovery if a single disk fails. - **RAID 6:** - Requires at least four disks. It adds a second layer of parity, allowing data recovery from up to two simultaneous disk failures. - **Parity Distribution:** - The parity data is distributed across all the disks in the array, rather than being stored on a single disk, to avoid a performance bottleneck. **Advantages:** 1. **Improved Performance:** - Offers enhanced read performance by striping data across multiple disks, while writes involve slightly more overhead due to parity calculation. 2. **Data Protection:** - Provides fault tolerance, allowing the system to withstand the failure of one disk (RAID 5) or two disks (RAID 6) without data loss. 3. **Efficient Storage Utilization:** - Compared to mirroring, RAID 5/6 uses storage capacity more efficiently by only allocating space for parity rather than complete data duplication. **Disadvantages:** 1. **Write Performance:** - Write operations can be slower than read operations due to the need to calculate and write parity information. 2. **Complexity:** - More complex to set up and manage compared to simpler RAID levels, requiring more processing power for parity calculations. 3. **Rebuild Time:** - Rebuilding a failed disk in the array can take a significant amount of time, during which performance might be degraded. **RAID (Redundant Array of Independent/Inexpensive Disks):** An array describes two or more drives working as a unit. They outlined several forms or "levels" of RAID that have since been numbered 0 through 6 (plus a couple of special implementations). Only a few of these RAID types are in use today: 0, 1, 5, 6, 10, and 0+1. 1. **RAID 0 (Disk Striping):** - **Configuration:** Requires at least two drives. - **Performance:** Stripes data across all drives to improve read/write performance. Is a mirror set that offers fault tolerance but does not increase data access. - **Redundancy:** Offers no fault tolerance, redundancy; if one drive fails, all data is lost. Back up data early and frequently. - Use Case: Suitable for applications where performance is critical and data loss is acceptable or data is backed up elsewhere. 2. **RAID 1 (Disk Mirroring/Duplexing):** - **Configuration**: Requires at least two drives (or any even number). - **Performance:** Offers read performance improvements (can read from either drive), but write performance is similar to a single drive. - **Redundancy:** Provides fault tolerance, it writes data to both drives at the same time if one drive falls the data is still available on the other. - Use Case: Ideal for critical data that needs protection, such as databases and OS drives. 3. **RAID 5 (Disk Striping with Distributed Parity):** - **Data Striping with Parity:** Data and parity are distributed across all drives. Each stripe uses n−1*n*−1 drives for data and one for parity. Parity rotates among the drives. - **Storage Capacity:** Total capacity equals the sum of all drives minus one, as one drive\'s worth of space stores parity. It requires a minimum of three hard disks. - **Fault Tolerance:** Can withstand a single drive failure without data loss. - **Performance:** Offers good read speeds, while write speed is affected by parity calculations, has striping with parity. - **Use Case:** Common in environments needing a balance of cost, performance, and redundancy, such as file and application servers. 4. **RAID 6 (Disk Striping with Extra Parity):** - **Configuration:** Requires at least four drives. - **Performance:** Similar to RAID 5 with a slight decrease in write performance due to dual parity calculations. - **Redundancy:** Can withstand up to two drive failures. - **Use Case:** Suitable for critical systems where data protection is paramount, such as large storage arrays and archival storage. 5. **RAID 10 (Nested, Striped Mirrors or RAID 1+0):** - Configuration: Requires a minimum of four drives. Consists of mirrored pairs that are striped together (known as a "stripe of mirrors"). Minimum of four drives, a pair of drives is configured as a mirror, and then the same is done to another pair to achieve a pair of RAID 1 arrays. The arrays look like single drives to the operating system or RAID controller. - **Performance:** High read and write performance, combining RAID 0\'s speed with RAID 1's data redundancy. - **Redundancy:** Excellent fault tolerance; can lose one adds fault tolerance to RAID-0 by mirroring each disk in the RAID-0 striped set with RAID-1. - **Storage Efficiency:** Effective storage capacity is half of total drive capacity (four 2-TB drives offer 4 TB usable storage), due to mirroring requires at least 4 hard disks. - **Setup and Maintenance:** Relatively straightforward to set up and maintain compared to RAID levels with complex parity arrangements. - **Use Case:** Beneficial for high-performance applications requiring quick data access and robust fault tolerance, like database management, virtualization, and high-transaction environments. Also ideal for personal computers and small businesses needing reliable storage without sacrificing speed. 6. **RAID 0+1 (Nested, Mirrored Stripes):** - **Configuration:** Requires a minimum of four drives; creates RAID 0 striped arrays first, then mirrors them. - **Performance:** Similar performance benefits to RAID 10. - **Redundancy:** Provides redundancy, but a failure in one half of the striped array requires a full rebuild after another drive failure. - **Use Case:** Useful for applications needing redundancy and performance, but with potentially more complicated recovery than RAID 10. **Implementing RAID** RAID levels describe different methods of providing data redundancy or enhancing the speed of data throughput to and from groups of hard drives. They do not say how to implement these methods. Once you have hard drives, the next question is whether to use hardware or software to control the array. Let's look at both options. **Software RAID vs. Hardware RAID** Software RAID and hardware RAID are two approaches to implementing RAID (Redundant Array of Independent Disks) configurations, each with its own advantages and disadvantages. Here's a comparison of the two: **Software RAID:** 1. **Implementation:** - Managed by the operating system using software utilities or built-in OS features. - Does not require dedicated hardware, as it uses system resources to perform RAID functions. 2. **Performance:** - Performance can be affected by the system\'s CPU load, as the CPU handles I/O operations and RAID processing. May experience lower performance compared to hardware RAID, especially under heavy loads. 3. **Cost:** - More cost-effective since it doesn\'t require specialized hardware. - Requires minimal investment in additional hardware components. 4. **Flexibility:** - More flexible with disk configurations and supports a wider variety of disk formats and setups. - Easier to modify or transfer RAID arrays between systems. 5. **Compatibility:** - Generally compatible with various operating systems, provided the OS supports the desired RAID levels. 6. **Management:** - RAID management tools are typically included in the OS, providing easy access and setup through software interfaces. 7. **Fault Tolerance:** - Offers varying levels of redundancy depending on the RAID level implemented, but recovery may take longer since it relies on system resources. **Hardware RAID:** 1. **Implementation:** - Implemented with dedicated RAID controller cards or integrated RAID controllers on motherboards. - The RAID controller manages all RAID functions independent of the OS. 2. **Performance:** - Generally offers better performance due to dedicated processing power designed specifically for RAID tasks, reducing CPU overhead. - Often includes advanced features like caching, which can enhance performance. 3. **Cost:** - Typically more expensive due to the need for additional hardware. - The cost can vary greatly depending on the features and capabilities of the RAID controller. 4. **Flexibility:** - Less flexible when it comes to configurations and modifications, as moving the RAID array to a different controller or system can pose compatibility issues. 5. **Compatibility:** - Compatibility primarily depends on the specific RAID controller used; transferring RAID configurations between different controllers may not always be possible. 6. **Management:** - Management tools are provided by the RAID controller manufacturer, which may offer advanced features like monitoring and alerting. - Configuration setups are usually accessible through a boot-time utility or management software. 7. **Fault Tolerance:** - Often includes advanced error recovery and rebuilding features, generally facilitating faster recovery from drive failures.  **SIM**: Check out the Chapter 8 Challenge! sim, "Storage Solution," to examine best RAID practices at https://www.totalsem.com/100x **Dedicated RAID Boxes** Many people add a dedicated RAID box to add both more storage and a place to back up files. These devices take two or more drives and connect via one of the ports on a computer, such as USB or Thunderbolt (on modern systems) or FireWire or eSATA (on older systems). This model is typical, offering three options for the two drives inside: no RAID, RAID 0, or RAID 1.  **Cabling SATA Drives** Installing SATA hard disk drives is relatively easy and straightforward process because there are no jumper settings to worry about at all, as SATA supports only a single device per controller channel. Simply connect the power and plug in the controller cable. the OS automatically detects the drive and it's ready to go. The keying on SATA controller and power cables makes it impossible to install incorrectly. Every modern motherboard has two or more SATA ports (or SATA connectors) built in. The ports are labeled (SATA 1, SATA 2, and so forth up to however many are included). Typically, you install the primary drive into SATA 1, the next into SATA 2, and so on. With nonbooting SATA drives, such as in M.2 motherboards, it doesn't matter which port you connect the drive to. Keep in mind the following considerations before implementing a HDD/SDD migration: - Do you have the appropriate drivers and firmware for the SSD? Newer Windows versions will load the most currently implemented SSD drivers. As always, check the manufacturer's specifications as well. - Do you have everything important backed up? **BIOS Support: Configuring CMOS and Installing Drivers** Every device in your PC needs BIOS support, whether it's traditional BIOS or UEFI. Hard drive controllers are no exception. Motherboards provide support for the SATA hard drive controllers via the system BIOS, but they require configuration in CMOS for the specific hard drives attached. **Configuring Controllers** As a first step in configuring controllers, make certain they're enabled. Most controllers remain active, ready to automatically detect new drives, but you can disable them. Scan through your CMOS settings to locate the controller on/off options. This is also the time to check whether the onboard RAID controllers work in both RAID and non-RAID settings. **Autodetection** If the controllers are enabled and the drive is properly connected, the drive should appear in system setup through a process called autodetection. Autodetection is a powerful and handy feature that takes almost all the work out of configuring hard drives. Motherboards use a numbering system to determine how drives are listed---and every motherboard uses its own numbering system! one common numbering method uses the term channels for each controller. The first boot device is channel 1, the second is channel 2, and so on. So instead of names of drives, you see numbers. **Enabling AHCI** On motherboards that support AHCI, you implement it in CMOS. You'll generally have up to three options/modes/HBA configurations: IDE/SATA or compatibility mode, AHCI, or RAID. Don't install modern operating systems in compatibility mode; it's included with some motherboards to support ancient (Windows XP) or odd (some Linux distros, perhaps?) operating systems. AHCI works best for current HDDs and SSDs, so make sure the HBA configuration is set to AHCI. **Troubleshooting Hard Drive Installation** Troubleshooting hard drive installation issues can help ensure that your hard drive is correctly set up and functioning as expected. Here's a guide to diagnosing common problems: **Pre-Installation Checks:** 1. **Compatibility:** - Ensure the hard drive type (HDD/SSD) is compatible with your motherboard (SATA, NVMe, etc.). 2. **Power Supply:** - Verify that your power supply unit (PSU) has enough power connectors and wattage to support the new drive. 3. **Cables:** - Check that you have the appropriate cables (SATA, power, etc.) and that they are in good condition. **Installation Steps:** 1. **Mounting the Drive:** - Ensure the hard drive is securely mounted in the drive bay. If using screws, confirm they are tightened but not overly tight. 2. **Connecting Cables:** - Double-check that both the data cable (SATA or NVMe) and power cable are properly connected. **Post-Installation Checks:** 1. **BIOS/UEFI Configuration:** - Restart the computer and enter BIOS/UEFI settings (usually by pressing F2, Delete, or Esc on boot). - Check if the new hard drive is detected in the storage configuration. 2. **Disk Management (Windows):** - If using Windows, go to **Disk Management (right-click** on This **PC → Manage → Disk Management**). - Ensure the hard drive is initialized and has a drive letter assigned. If not, **initialize the disk and create a new volume.** 3. **Format the Drive:** - If it\'s a new drive, you may need to format it before use. Right-click on the unallocated space in Disk Management and select New Simple Volume. **Common Issues and Solutions:** 1. **Drive Not Detected:** - Ensure all connections (power and data) are securely attached. - Try a different SATA port or data cable. - Check for firmware updates for the motherboard that may improve compatibility. 2. **Drive is Detected but Not Accessible:** - Confirm the drive is initialized and formatted using Disk Management. - Check for errors under Properties in Disk Management or run CHKDSK in the command prompt. 3. **Slow Performance:** - Ensure the drive is connected to the correct SATA port (for example, SATA III for SSDs). - Check for fragmentation (most pertinent for HDDs) or SSD health using diagnostic tools. 4. **Overheating:** - Ensure adequate ventilation and that the drive is not blocked by cables or other components. - Consider using additional cooling options like fans if necessary. 5. **Noisy Drive:** - A new drive should operate quietly. Excessive noise might indicate a defective drive. Listen for unusual sounds like clicking or grinding. **Additional Tips:** - **Check for Updates:** - Ensure your OS and drivers are up to date, as this can impact detection and performance. - **Try Different Systems:** - If possible, test the hard drive in another system to rule out compatibility issues or motherboard problems. - **Examining SMART Data:** - Use diagnostic software to check the drive's SMART data for potential issues indicating it may be failing.