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For those that like videos more than text, there is a youtube video from last year [1] that explain the feature (unless it's changed since ,but it seems not to
by mrighele 5y ago
For those that like videos more than text, there is a youtube video from last year [1] that explain the feature (unless it's changed since ,but it seems not to be the case).
One downside that I see of this approach, if I understand it correctly, is that the data already present on disk will not take advantage of the extra disk per slice. For example, if I have a raidz of 4 disks (so 25% of space "wasted"), and add another disk, new data will be distributed on 5 disks (so 20% of space "wasted") but the old data will keep using stripes of 4 blocks, they will just be reshuffled between the disks. Do I understand it correctly ?
[1] https://www.youtube.com/watch?v=yF2KgQGmUic https://www.youtube.com/watch?v=yF2KgQGmUic
- GauntletWizard 5y agoThat is correct. There are planned solutions for rewriting all your data, though they won't play nicely with one of ZFS's other most important features - Snapshots. The current plan is basically to have a nice userspace utility that will rewrite all your data in-place, but that will cause you to rereplicate everything over your snapshots.
- mrighele 5y agoThanks for your answer. The point about the snapshots is a very good one, for some reasons I didn't think about it. Rewriting data in place can be tricky, if you have old enough snapshots the newly added space may not be enough. I hope they will find a good enough solution.
- rincebrain 5y agoYes, old data keeps the old data:parity ratio unless you do something like cp or zfs send|recv it and destroy the old copy.