RAID 5T2

Learn how data is written to a RAID 5T2 array when using the Easy Tier® function.

RAID 5T2 is a RAID level that provides RAID 5 protection when using the Easy Tier function utilizing two different tiers of physical disk that have unique performance characteristics. Each tier functions as a single redundancy group and stripes data across all disks in the tier. Each tier is RAID 5 protected and writes array parity data across all the disks in the tier. For a RAID 5T2 array that has one tier of three SSD disks and another tier of four HDD disks, array data and parity information is written in the following pattern:

If a disk fails in either RAID 5 tier, you can continue to use the entire array. Each tier can contain a failed disk and the array continues to function. A RAID 5T2 array that is operating with a single failed disk in either or both tiers is said to be operating in degraded mode. Whenever data is read from a degraded disk array, the array controller recalculates the data on the failed disk by using data and parity blocks on the operational disks. If a second disk fails in either tier, the entire array is placed in the failed state and is not accessible.