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FreeNAS ZFS Disk Layouts (RAID Levels)

Compare RAID levels according to their capabilities.
Information below provided by Microsemi, IBM and Adaptec.
The following information provides data redundancy, usable disk capacity, read performance, and write performance for each RAID level.
For the most part you have two viable choices; RAID 10 OR RAID 6 (RAIDZ2).
As a very rough estimate, plan on RAID 10 to overall perform 1.5 times faster than RAID 6.  The ratio of read to write operations will dramatically affect the comparison.  RAID 6 performance has much lower write performance due to parity.  See charts below.

RAID 10 (Striped RAID 1 sets): Combines RAID 0 striping and RAID 1 mirroring. This level provides the improved performance of striping while still providing the redundancy of mirroring.  RAID 10 is the result of forming a RAID 0 array from two or more RAID 1 arrays. This RAID level provides fault tolerance — up to one disk of each sub-array may fail without causing loss of data.

What is the chance that I will experience a t…

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