RAID Level Comparison: RAID 0, RAID 1, RAID 5, RAID 6 and RAID 10
With the increasing demand for higher storage capabilities, improved performance, and data loss recovery, RAID has emerged as a viable storage solution. RAID stands for Redundant Array of Inexpensive Disks or Redundant Array of Independent Drives. This technology is developed to increase the performance and reliability of data storage. A RAID system consists of multiple disks that work in parallel. This set up can comprise hard discs or SSDs (Solid State Drives). All these drives are linked together to prevent data loss and improve performance. This becomes possible by mirroring data on one or more disks in the same array. Disk mirroring helps in preserving data if one or more disk fails. To improve performance, a stripping technique is used that spreads data over multiple disk drives.
RAID storage device can be configured in multiple ways, known as RAID levels. The different RAID levels determine how data is dispersed among multiple disks. Initially, there were six levels of RAID – 0 to 5. However, as the number of levels expanded, the RAID level has been divided into three categories: standard, nested, and nonstandard RAID levels. The Standard RAID level consists of RAID 0- 6. The Nested RAID (a combination of RAID levels) includes RAID 10 (RAID 1+0), RAID 01 (RAID 0+1), and RAID 50 (RAID 5+0). The Nonstandard RAID levels are RAID 7, RAID 1E, RAID S, and more. All these different RAID levels offer a different level of performance and reliability. However, based on the techniques used, the most common types of RAID are:
RAID Level 0
RAID Level 1
RAID Level 5
RAID Level 6
RAID Level 10
RAID Levels Comparison
There are multiple RAID levels and each level offers a unique combination of performance and redundancy. The RAID level you choose will determine the speed and fault tolerance you can expect from the RAID set up. While choosing a RAID level, you need to consider a lot of factors such as cost, reliability, capacity, and performance. So, let’s compare the most popular RAID levels to help you select the best level for your storage system. Below we’ve discussed the common RAID levels and the pros and cons of each type.
RAID 0, also called striping, works by dividing data evenly across two or more drives (HDD or SSD). RAID o divides data into blocks and distributed across the drives in the array. This helps in speeding up performance but RAID 0 fails to provide redundancy. This means that this level offers superior I/O performance but cannot be used for mission-critical situations. The performance of RAID 0 can be further improved by using multiple controllers- one controller per disk. Due to superior overall performance, RAID 0 is best suited for application where improved performance is the primary driver. It is ideal for non-critical data storage where high read/write speed is more important. Disk striping is most suited for large applications such as on an image retouching or video editing. However, due to a lack of data redundancy, any raid data failure could result in complete data loss.
Superior performance- both in reading and write operations
RAID 0 is the most affordable and easy to set up
Full capacity use, no overhead
The technology is easy to implement
RAID 0 is not fault-tolerant (no redundancy). Single drive failure could lead to complete data loss.
RAID level 1 store data twice by writing them to the data drives, as well as the mirror drives. With mirroring and duplexing, data is duplicated on a second disk. This means that if one drive fails, data can be read or written from the other drive. RAID 1 offers fault tolerance because it duplicates data by simultaneously writing on two storage devices. Duplexing ensures that even if a controller fails, the system won’t breakdown. In RAID 1 each disk has an exact copy on another disk to ensure protection against data loss. But on the downside, RAID 1 doesn’t provide any performance improvements.
This technique does not include parity or striping. This RAID level can be used for mission-critical storage and small servers.
Increased read speed
Simple technology, easy to set up
Doesn’t require data rebuilding if a driver fails
Uses only half of the storage capacity because all data get written twice
If a drive fails, you need to power down your computer to replace failed drive
RAID level 5 uses disk striping and parity to strip data across three or more drives. This is the most popular RAID level for organizing independent disks. As one of the most common secure RAID levels, RAID 5 can comprise 3 to 16 drives. In this technique, data is striped but not duplicated. Here the parity data are spread across all drives to rebuild data if needed. This means that RAID 5 array can withstand a single drive failure without losing data. This RADI level ensures protection against disk failure, as well as provides high performance and reliability. RAID 5 offers a great combination of data security and improved read/write performance. With good storage, superior security, and reliable performance, RAID 5 can be used for applications that have a limited number of data drives.
Better performance because data can be read or written simultaneously across multiple drives
Fault-tolerant because even if a drive fails, data can be accessed from other drives
Consistent access to all data
Uses only half of the storage capacity
It is a complex technology and RAID rebuild may take a day or longer
Parity overhead that causes lower performance rates
RAID 6 is one of the most commonly used RAID levels. It is similar to RAID 5, however, this level writes the parity data to two drives. RAID 6 needs at least 4 drives and can withstand 2 drives failures at a time. This technique combines block-level striping with double distributed parity. RAID 6 strips the data and parity information across all drives and redundancy information is duplicated. This level offers improved performance and can withstand a complete failure of two drives. RAID 6 is considered safer than RAID 5 but data writing can be slower than RAID 5. This happens because RAID 6 involves calculating the additional parity data. RAID 6 is the right choice for the application servers that use many large drives for data storage.
Data reading transactions are super fast
Data can be accessed even when two drives fail
Write data transactions are slower than RAID 5
Complicated to implement and rebuilding an array can take a long time
RAID 10 (1+0)
RAID 10 combines RAID 0 and RAID 1 where data is mirrored and striped simultaneously. By combining RAID levels 1 and 0, this level achieves the benefits of both levels. This means that RAID 10 gets the high performance of RAID 0 and fault-tolerance of RAID 1. RAID 10 has a minimum of four (4) disks, where two (2) disks are striped and mirrored onto two (2) other disks to create a single array. It is noteworthy here that RAID 10 and 01 are not the same.
Quick to rebuild
RAID LEVEL COMPARISON