What is RAID 0?
RAID 0, also known as disk striping, is a type of RAID (Redundant Array of Independent Disks) configuration that spreads data evenly across two or more drives with no parity or mirroring (PCMag, 2023). The main goal of RAID 0 is to increase performance by distributing the load across multiple hard drives or solid state drives.
In RAID 0, data is split up into blocks that get written across the drives in the array simultaneously. For example, Drive 1 gets Block 1, Drive 2 gets Block 2, Drive 3 gets Block 3, and so on. This allows read and write operations to be performed in parallel, improving speed and bandwidth (Partition Wizard, 2020). The more drives in the RAID 0 array, the greater the performance gains.
However, RAID 0 provides no data redundancy or fault tolerance. If one drive fails, all data across the entire array will be lost. For this reason, RAID 0 is generally used in non-critical storage environments where performance is the priority over reliability (EaseUS, 2022). Overall, RAID 0 is best suited for applications that demand high I/O performance like video editing, gaming, image rendering, and running virtual machines.
Benefits of RAID 0
RAID 0 offers increased performance and full storage capacity utilization compared to a single drive (1). By striping data across multiple drives, RAID 0 allows for parallel read and write operations, improving overall speed. This makes RAID 0 well-suited for applications that demand high throughput like video editing, gaming, and database access (2).
Because RAID 0 combines the capacity of all drives in the array, it allows you to utilize the full storage potential. A two-drive RAID 0 array will have double the capacity of a single drive. This makes RAID 0 a cost-effective way to increase storage space while also gaining speed improvements (3).
Sources:
(1) https://www.quora.com/What-are-the-benefits-and-disadvantages-of-RAID-0
(2) https://medium.com/@PITSGlobalDataRecoveryServices/raid-0-explained-d8edb9be5a9e
(3) https://www.reddit.com/r/homelab/comments/15jkwt9/is_a_raid_0_backup_array_as_stupid_as_it_sounds/
Drawbacks of RAID 0
The biggest drawback of RAID 0 is that it has no fault tolerance. This means that if one drive in the RAID 0 array fails, the entire array will fail and all data will be lost. This is because data is spread evenly across all drives in the array, so if one drive goes down, parts of the data stored on that drive will be missing from each stripe. Without those missing pieces, none of the data can be reconstructed.
According to IONOS [1], this lack of fault tolerance makes RAID 0 more prone to failure than single drives. Because RAID 0 combines multiple disks, the probability of any one disk failing is higher than with a single disk. This increased chance of failure makes RAID 0 a poor choice for data that cannot be easily replaced or recreated.
Overall, the complete data loss that results from a single drive failure is a major downside of RAID 0 arrays. Users have to weigh the performance gains against the substantial risks.
RAID 0 Requirements
In order to setup a RAID 0 array, there are a few minimum requirements that need to be met:
First, RAID 0 requires a minimum of two identical hard drives (according to TechRepublic). The drives need to be the same size and ideally the same model for optimal performance. RAID 0 can be created with drives of differing sizes, but the array will be limited to the size of the smallest drive.
Second, a RAID controller is required to manage the RAID 0 array (according to Lifewire). This can be a hardware RAID controller card or a software-based controller. The RAID controller stripes data across the drives and presents the array to the operating system as a single logical drive.
Without meeting these two minimum requirements, a RAID 0 array cannot be created. The array also requires proper cabling to connect the drives to the RAID controller. Provided the requirements are met, RAID 0 can deliver improved performance compared to a single drive.
How Data is Stored in RAID 0
In RAID 0, data is distributed across multiple drives by a technique called striping. This means the data is split into evenly sized blocks and the blocks are written in stripes across multiple drives simultaneously (https://www.techtarget.com/searchstorage/definition/RAID-0-disk-striping). For example, if there are 2 drives, the first block of data would be written to the first drive, the second block would be written to the second drive, the third block back to the first drive, and so on in alternating fashion.
The key things to know about how data is stored in RAID 0 are:
- Data is split into blocks and striped across multiple drives
- There is no parity or duplication of data blocks
- Data is distributed evenly across drives for performance
- If one drive fails, all data will be lost
By striping data across drives with no parity or duplication, RAID 0 optimizes storage capacity and performance. However, it provides no fault tolerance or redundancy if a drive fails. The tradeoff is increased speed and size at the cost of reliability (https://www.hellotech.com/blog/what-is-raid-0-1-5-10).
Performance of RAID 0
RAID 0 offers very fast read and write speeds compared to a single drive because it combines the performance of multiple drives. With RAID 0, reads and writes are spread across multiple drives in parallel, allowing the full bandwidth of each drive to be utilized. This means if you combine two 500 MB/s SSDs in RAID 0, you could theoretically achieve read/write speeds up to 1000 MB/s, doubling the performance of a single drive.
According to benchmarks by Tom’s Hardware, four Samsung 980 Pro NVMe SSDs configured in RAID 0 reached read speeds over 6,500 MB/s and write speeds around 5,500 MB/s 1. For intense workloads involving large sequential reads and writes, like 4K video editing or 3D modeling, RAID 0 can provide a significant speed boost.
However, for many everyday tasks and more random workloads, the performance gains of RAID 0 may not be as noticeable. The speed increase mainly applies to large contiguous reads and writes. But for small random accesses, RAID 0 won’t help much compared to a single fast SSD.
Reliability of RAID 0
RAID 0 has very poor reliability because it offers no redundancy or fault tolerance. This means that if any single drive in the RAID 0 array fails, all data across the entire array will be lost. There is no protection against drive failures in RAID 0.
With multiple disks in RAID 0, the overall chance of disk failure increases. According to calculations on the RAID Reliability Calculator website, a 2-drive RAID 0 array has a 5.8% chance of failure within the first year. This increases to 11.1% chance of failure within the first year for a 4-drive RAID 0 array. More disks equals lower reliability.
Because of the complete lack of redundancy, RAID 0 should never be used for mission critical data or in situations where data integrity and reliability are important. The improved performance comes at the huge cost of no fault tolerance. RAID 0 is only suitable for non-critical data where complete data loss is an acceptable risk.
Use Cases for RAID 0
RAID 0 is best suited for scenarios that require maximum disk performance and speed. Some common use cases that can benefit from RAID 0 include:
Video Editing – Video editing and production involves working with large media files that need fast read/write speeds. RAID 0 provides the bandwidth for smooth editing, rendering, and encoding of high resolution video (https://darwinsdata.com/which-raid-level-increases-performance-but-provides-no-redundancy/).
Gaming – Gamers want fast load times and performance when playing graphics-intensive games. RAID 0 enables games and levels to load quicker by spreading data across multiple disks (https://darwinsdata.com/which-type-of-raid-is-known-as-disk-striping/).
High Throughput Applications – Any application that needs to read/write large volumes of data as fast as possible can benefit from the increased bandwidth of RAID 0. Examples include data analytics, financial modeling, scientific computing, and more.
Alternatives to RAID 0
While RAID 0 provides fast performance, it does not provide any redundancy or fault tolerance. If one drive in a RAID 0 array fails, all data across the array will be lost. Therefore, RAID 0 should not be used for any long-term or critical data storage.
Some alternatives that provide fault tolerance include:
- RAID 1 – Also known as disk mirroring, RAID 1 duplicates all data across two or more drives. If one drive fails, the data is still accessible from the other mirrored drive(s). RAID 1 provides redundancy but reduces total capacity. https://softraid.com/raid_uses/
- RAID 5 – Uses striping with distributed parity, providing fault tolerance with minimal capacity loss. If one drive fails, the parity blocks allow data to be rebuilt. RAID 5 requires at least 3 drives.
- RAID 10 – A nested/hybrid RAID level that combines mirroring and striping for both speed and redundancy. RAID 10 requires a minimum of 4 drives.
For critical data or long-term storage, RAID levels like RAID 1, 5, or 10 are recommended over RAID 0 to provide protection against drive failures.
How Many Drives Does RAID 0 Use?
RAID 0 requires a minimum of two drives to create a RAID 0 array. According the manufacturer LSI, their Host Bus Adapters supporting Integrated RAID allow for a minimum of two drives in RAID 0 configuration. While two drives is the minimum, more can be used.
By spreading data across multiple disks, RAID 0 is able to enhance disk performance through increased parallelism. Using additional drives expands the RAID 0 array, allowing for larger overall storage capacity and increased performance. Most implementations allow up to 32 disks in a single RAID 0 array.
The primary benefits of using more than two disks in RAID 0 are enhanced disk performance and additional storage capacity. However, using more disks also increases the chance for failure, as data loss will occur if any single drive fails. The ideal number of disks depends on the specific use case and desired balance of performance, capacity, and redundancy.