SnapRAID - Parity - Split Parity

Split the parity across multiple partitions.

In the configuration file, just put more files in the same 'parity' line, separated by , (comma).

The parity disk needs to be as large or larger than the data disks.

NOTE: Historically, adding larger data disks to the array always required to similarly needing to also increase the parity disk to be as large or larger than the largest data disk.

  • This would mean needing to potentially acquire an additional large disk to ensure the parity was also as larger as this new data disk.
  • More cost…

Assuming the array is made up of (4) 4TB data disks and (1) 4TB parity disk.

  • If a new 8TB data disk was added to the array, then the current 4TB parity disk would not be large enough.
  • This would require to also having to replace the parity disk with a similar 8TB disk.

With split parity, there is no need to replace the parity disk with a new larger disk.

  • Instead, some smaller disks can be joined together as one complete set of parity.

For example, as there is a new 8TB data, this means that there should also be at least 8TB of parity.

  • (2) 4TB disks could be used, joined together as one complete set of parity; or
  • (4) 2TB disks, could be similarly joined.

Example

/etc/snapraid.conf
parity /mnt/split-parity/parity1-disk1/part1.parity,/mnt/split-parity/parity1-disk2/part2.parity
2-parity /mnt/split-parity/parity2-disk1/part1.parity,/mnt/split-parity/parity2-disk2/part2.parity

Split Parity