RAID 10T2

Learn how data is written to a RAID 10T2 array when using the Easy Tier® function.

RAID 10T2 is a RAID level that provides RAID 10 mirrored pair redundancy when using the Easy Tier function utilizing two different tiers of physical disk that have unique performance characteristics. Each tier must contain an even number of disks. A minimum of two disks are needed to create a RAID 10T2 tier. The data is striped across the mirrored pairs in each tier. For example, a RAID 10T2 array that has one tier of four SSD disks and another tier of 6 HDD disks would have data written on it in the following pattern:

Figure 1. RAID 10T2

RAID 10T2 tolerates multiple disk failures. If one disk in each mirrored pair fails, the array continues to function, operating in degraded mode. You can continue to use the array because for each failed disk, the data is stored redundantly on its mirrored pair. However, if both members of a mirrored pair fail, the array will be placed in the failed state and will not be accessible.

When a RAID 10T2 disk array is created, the controller automatically attempts to select the disks for each mirrored pair from a different controller connector (a different cable to a different device enclosure). For example, if four disks selected for a disk array are located on one of the controller connectors and another four disks selected are located on another of the controller connectors, the controller automatically attempts to create each mirrored pair from one disk on each controller connector. In the case of a controller port, cable, or enclosure failure, each mirrored pair continues to operate in a degraded mode. Such redundancy requires careful planning when you are determining where to place devices.