RAID stands for Redundant Array of Independent Disks and is a form of data management/backup that spreads your data across multiple hard drives. To learn more about what RAID is, visit this page.

Table of Different RAID Levels

RAID Level Description Advantages Disadvantages
Combines two or more hard drives together and treats them as one large volume. For example, two 250GB drives combined in a RAID 0 configuration creates a single 500GB volume. RAID 0 is used by those wanting the most speed out of two or more drives. Because the data is split across both drives, the speed of data reading and writing increases as more disks are added. Every drive has a limited lifespan and each disk adds another point of failure to the RAID. Every disk in a RAID 0 is critical – losing any of them means the entire RAID (and all of the data) is lost.
Mirroring creates an exact duplicate of a disk. Every time you write information to one drive, the exact information is written to the other drive in your mirror. Important files (accounting, financial, personal records) are commonly backed up with a RAID 1. This is the safest option for your data. If one drive is lost, your data still exists in its complete form, and takes no time to recover. Your investment in data safety increases your drive costs since each RAID 1 volume requires two drives.
RAID 2 An obsolete implementation of striping similar to RAID 0 – it stripes at the bit level instead of by blocks.
RAID 3 A rare implementation of parity striping. Its limitation is that it cannot service multiple requests.
RAID 4 A rare implementation of parity striping at the block level with an entire disk dedicated to parity data. Similar to RAID 5.
RAID 5 (parity striping) A common RAID setup for volumes that are larger, faster, and more safe than any single drive. Your data is spread across all the drives in the RAID along with information that will allow your data to be recovered in case of a single drive failure. At least three drives are required for RAID 5. No matter how many drives are used, an amount equal to one of them will be used for the recovery data and cannot be used for user data. You can lose any one disk and not lose your backup data. Just replace the disk with a new one. Your investment in data safety increases your drive costs since at least three drives are needed.
RAID 6 Very similar to RAID 5, but adds an additional parity block of recovery information. It allows for the failure of two disks simultaneously with no data loss. Slightly slower than RAID 5 on writes but there is no added delay for reads.
RAID 10 (RAID 1+0) RAID 10 works by striping and mirroring your data across at least two disks. RAID 10 is secure because mirroring duplicates all your data. It’s fast because the data is striped across two or more disks, meaning chunks of data can be read and written to different disks
RAID 50 (RAID 5+0) A RAID 50 combines the straight block-level striping of RAID 0 with the distributed parity of RAID 5. This is a RAID 0 array striped across RAID 5 elements. It requires at least 6 drives. Provides great balance between storage performance, storage capacity, and data integrity that’s not necessarily found in other RAID levels.One drive from each of the RAID 5 sets could fail without loss of data. The time spent in recovery (detecting and responding to a drive failure, and the rebuild process to the newly inserted drive) represents a period of vulnerability to the RAID set.
RAID 60 (RAID 6+0) A RAID 60 combines the straight block-level striping of RAID 0 with the distributed double parity of RAID 6. That is, a RAID 0 array striped across RAID 6 elements. It requires at least eight drives. A great fit when you need higher usable capacity and better reliability. Slight loss in write speed and performance.

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