RAID level-5EE is similar to RAID level-5 but with a built-in distributed spare and faster rebuild times. Like RAID level-5, this RAID level stripes data and parity across all of the drives in the disk group.
RAID level-5EE offers both data protection and increased throughput. When a disk group is assigned RAID level-5EE, the capacity of the logical device is reduced by the capacity of two physical drives in the disk group: one for parity and one for the spare.
The spare drive is part of the RAID level-5EE disk group. The spare is interleaved with the parity blocks, as shown in the following example. This allows data to be reconstructed more quickly if a physical drive in the disk group fails. With such a configuration, you cannot share the spare drive with other disk groups. If you want a spare drive for any other disk group, you must have another spare drive for those disk groups.
RAID level-5EE requires a minimum of four drives and, depending upon the level of firmware and the stripe size, supports a maximum of 8 or 16 drives. RAID level-5EE is also firmware-specific.
The following illustration is an example of a RAID level-5EE logical device.
Start with four physical drives. | ![]() |
Create a disk group using all four physical drives. | ![]() |
Then create a logical device within
the disk group.
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The data is striped across the drives,
creating blocks in the logical device.
The storage of the data parity (denoted by *) is striped, and it shifts from drive to drive as it does in RAID level-5E. The spare drive (denoted by S) is interleaved with the parity blocks, and it also shifts from drive to drive. |
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If a physical drive fails in the
disk group, the data from the failed drive is reconstructed. The disk group undergoes
compaction, and the distributed spare drive becomes
part of the disk group. The logical device remains RAID level-5EE.
When you replace the failed drive, the data for the logical device undergoes expansion and returns to the original striping scheme. |
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RAID level-5EE offers the following advantages and disadvantages.
Advantages | Disadvantages |
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