Certified - CompTIA Cloud+

R A I D, which stands for Redundant Array of Independent Disks, is a method of combining multiple physical disk drives into a single logical unit to enhance performance, increase capacity, or provide redundancy. In cloud and on-premises environments, R A I D is used to reduce the risk of data loss, speed up access to data, or balance both goals. By striping, mirroring, or adding parity across multiple disks, storage administrators can fine-tune how data is stored and recovered. The Cloud Plus certification includes an understanding of R A I D levels as part of designing resilient and efficient storage architectures that meet operational requirements for performance and fault tolerance.
Selecting the correct R A I D level is essential when planning for performance and availability. Each level presents a different mix of speed, capacity efficiency, fault tolerance, and write behavior. Some configurations maximize performance but provide no redundancy, while others favor data protection with trade-offs in write speed or capacity usage. Knowing these trade-offs helps cloud professionals design systems that are aligned with workload patterns and business continuity goals. The exam often presents scenarios that require selecting an appropriate R A I D configuration based on factors such as read and write activity, disk failure risk, and rebuild complexity.
R A I D zero, also known as striping, distributes data evenly across two or more drives to maximize read and write speed. Because there is no redundancy, a failure in any single drive results in total data loss. While it offers the highest throughput, it is suitable only in low-risk environments where data loss is acceptable or where separate backup solutions are in place. The Cloud Plus certification includes R A I D zero as a solution for high-speed caching, scratch storage, or temporary data workloads where performance is the top priority and fault tolerance is not needed.
R A I D one, or mirroring, duplicates data on two or more drives. Each write operation is performed simultaneously on all mirrored disks, which provides a high level of redundancy. In the event of a single drive failure, the system continues to operate normally with no data loss. This makes R A I D one ideal for mission-critical systems that require high availability. However, write performance may be slower than R A I D zero due to the overhead of writing to multiple disks. Candidates should recognize scenarios where mirroring is preferred, particularly in operating system volumes or small but essential databases.
R A I D five adds parity to the striping approach by distributing both data and parity information across three or more drives. The parity data enables recovery if any one drive fails, making R A I D five a balance between performance, capacity, and fault tolerance. While write performance can be slower due to the overhead of calculating and writing parity, the configuration is space-efficient compared to R A I D one. The exam may ask you to understand how parity works, how the system rebuilds data after a failure, and which workloads benefit most from this balance of attributes.
R A I D six extends the parity concept by allowing for two drives to fail without data loss. It requires a minimum of four drives and adds additional write overhead to calculate and store two separate parity blocks. R A I D six is particularly useful in large disk arrays where the likelihood of a second failure during a rebuild is higher. This configuration is favored in mission-critical environments that demand a higher level of fault tolerance than R A I D five can provide. For the exam, you must understand when dual parity is necessary and how to weigh the trade-off between performance and protection.
R A I D ten, sometimes referred to as one plus zero, combines mirroring and striping to deliver both performance and redundancy. It requires at least four drives, as data is first mirrored and then striped. This configuration offers faster performance than R A I D one alone and better redundancy than R A I D zero. If a single drive in a mirrored pair fails, the system continues to function normally, and data can be rebuilt from the remaining drive. Candidates should use R A I D ten in scenarios where both high speed and fault tolerance are required, such as high-transaction databases or virtualization hosts.
Performance comparisons between R A I D levels highlight the differences in speed and redundancy. R A I D zero provides the fastest read and write speeds but no fault tolerance. R A I D ten delivers near R A I D zero performance while adding full redundancy. R A I D five and R A I D six strike a balance between performance and protection, with R A I D six offering greater durability at the cost of slower writes. When selecting a R A I D level, consider the read and write ratio of the application, the acceptable level of risk, and the expected rebuild time. The Cloud Plus exam includes questions where workload characteristics must be matched to R A I D features.
Write penalties and parity overhead become critical when analyzing R A I D five and R A I D six. Parity calculations introduce additional write cycles, which can significantly affect performance, especially in write-heavy environments. R A I D six, with its dual parity scheme, generally suffers greater write penalties than R A I D five. These write delays can lead to bottlenecks in systems that generate large numbers of write operations. For the exam, you may be asked to choose the correct R A I D level for a write-intensive workload, where understanding parity overhead is necessary for making the optimal choice.
Rebuild time and associated risks must be considered during R A I D planning. As disk sizes increase, so does the time it takes to rebuild data after a drive failure. During this rebuild window, the array is at increased risk—especially for R A I D five, where a second failure during rebuild results in data loss. R A I D six reduces this risk by tolerating two drive failures, and R A I D ten shortens rebuild times due to its mirrored design. Candidates must understand how rebuild behavior affects operational resilience and how to plan for acceptable recovery time in the event of failure.
Storage efficiency refers to how much usable space remains after accounting for parity or mirroring. R A I D zero offers one hundred percent usable capacity because there is no redundancy. R A I D one, which mirrors all data, offers only fifty percent efficiency. R A I D five and R A I D six efficiency varies depending on the number of disks, with R A I D five reserving one disk for parity and R A I D six reserving two. When designing a storage solution, it is critical to calculate how much usable capacity will be available and whether it meets the system’s needs. The Cloud Plus exam includes scenarios requiring this type of capacity planning.
There is a distinction between software-based and hardware-based R A I D configurations. Software R A I D uses the host operating system to manage the R A I D array and is often less expensive but potentially slower. Hardware R A I D uses a dedicated controller card with its own processor and memory, often offering better performance, advanced features, and greater reliability. Some controllers support features like battery-backed cache or hot spare management. For the exam, be prepared to evaluate which configuration is appropriate based on cost, performance, and system complexity, and to recognize common hardware-related limitations.
For more cyber related content and books, please check out cyber author dot me. Also, there are other prep casts on Cybersecurity and more at Bare Metal Cyber dot com.
The use of R A I D in cloud environments differs significantly from on-premises configurations. In many cloud service models, especially managed storage offerings, the R A I D configuration is abstracted away and handled by the provider. For example, block storage volumes in an infrastructure as a service environment may appear as standalone devices, while in reality they are backed by redundant storage clusters using proprietary R A I D or replication schemes. However, in certain cloud scenarios—particularly when using infrastructure as a service with control over virtual machine instances and attached volumes—administrators may manually configure software R A I D inside those instances. The Cloud Plus certification includes awareness of both managed and unmanaged storage models and the implications for fault tolerance and performance.
Monitoring the health of R A I D arrays is critical to maintaining storage reliability. A degraded R A I D array indicates that one or more disks have failed or are experiencing issues, and that the system is operating in a vulnerable state. Using monitoring tools such as S M A R T data, R A I D controller logs, or management dashboards allows administrators to detect early signs of disk failure. Configuring alerts that notify administrators of rebuild status, missing drives, or parity inconsistencies is essential for proactive system management. For the exam, candidates must understand how to configure and interpret health indicators to ensure timely intervention and recovery.
It is important to recognize that R A I D is not a substitute for a proper backup strategy. While R A I D improves availability and minimizes downtime due to hardware failure, it does not protect against data corruption, accidental deletion, or malicious encryption from ransomware. A comprehensive data protection plan includes both R A I D for fault tolerance and regular backups for data recovery. Cloud Plus candidates must understand this distinction and plan for both. The exam may include questions designed to evaluate whether you can distinguish between availability-focused configurations and full data protection strategies.
Hybrid R A I D configurations combine multiple R A I D levels to address performance and redundancy requirements in large-scale arrays. For example, R A I D fifty combines R A I D five groups with striping, offering greater capacity and performance than a single R A I D five group. R A I D sixty extends this concept with dual parity. These configurations are commonly used in storage systems that manage many disks and need to improve I O P S while maintaining tolerance for multiple drive failures. Candidates must be familiar with hybrid R A I D structures and when they are appropriate for environments with large or high-demand workloads.
File system compatibility is an important consideration when deploying R A I D. Some file systems work more efficiently with certain R A I D levels or support advanced features like journaling, snapshotting, or checksumming that complement the array’s behavior. Operating systems must also recognize the R A I D structure and interact with it correctly. Tuning the file system and the R A I D configuration together can optimize performance and reduce the risk of file system corruption. For the exam, you may be asked how to ensure compatibility between the operating system and the chosen R A I D setup or how to troubleshoot file system issues arising from misalignment.
Booting from a R A I D array introduces additional complexity. Most commonly, R A I D one or R A I D ten is used for boot volumes, since these levels provide redundancy and allow the system to continue operating if one drive fails. However, bootloaders must support the underlying R A I D structure, and drivers must be present during the initial system startup. A misconfigured boot array can lead to unbootable systems, especially after hardware changes or updates. The Cloud Plus certification includes awareness of these risks, and you may be asked how to recover a failed boot array or design a resilient operating system deployment using R A I D.
R A I D also plays a role in virtualized environments, where virtual disks are often stored on physical volumes that reside on R A I D-backed storage. Hypervisors such as VMware or Hyper-V add an abstraction layer, but the underlying storage architecture still impacts performance and availability. In some designs, R A I D may be used at both the hypervisor host level and the storage array level. Candidates must understand how virtualization interacts with R A I D configurations and plan accordingly, ensuring that redundancy is not compromised by overlapping or conflicting layers of protection. The exam may include scenarios requiring planning across both host and storage domains.
To summarize, R A I D is a powerful tool for balancing performance, capacity, and redundancy in both cloud and on-premises environments. Each level—whether R A I D zero for speed, R A I D one for redundancy, R A I D five and six for parity, or R A I D ten for a hybrid approach—offers unique advantages and trade-offs. The Cloud Plus certification requires not just familiarity with these levels, but also the ability to apply them in practical situations. Understanding how rebuild times, write penalties, storage efficiency, and controller features influence system behavior ensures you can design storage that is both fast and reliable under real-world conditions.
When designing a storage solution, R A I D should be viewed as one element in a larger architecture that includes backups, monitoring, and compatibility with the application layer. The choice of R A I D level must align with workload requirements, risk tolerance, and operational constraints. Whether you're deploying a small database server or a massive virtualized infrastructure, mastering the behavior and application of each R A I D level is essential for success in cloud computing and critical for passing the Cloud Plus certification.