discX

Specifies a set of discs.

SetNumber

The set number of the RAID disc, referenced by each account.

BlockSize

The block size of the file system (usually 2048). Under BSD with FFS, set this to your file system's fragment size (most likely an 8th of the block size).

Dir0

The first directory in the RAID array.

Dir1

The second directory in the RAID array. If you do not wish to use the built-in RAID functionality, this field should be set to the same as Dir0. You should not use the built-in RAID if you have a hardware RAID solution or if you're using another type of software RAID (like md on Linux).

Dir2

The third directory in the RAID array. The same notes that apply to Dir2 also apply to Dir3.