raid1c3 in metadata for btrfs
Closed this issue · 2 comments
Hello,
Regarding metadata level on btrfs it's complicated. When you have 3 or more disks it makes sense to have raid1c3 regardless of data level. Only if your kernel does not support it, or you have only 2 disks it must be raid1.
That could explain why raid6 fails:
dm-crypt + btrfs: 30KB corruption on 2/4 raid6 disks
btrfs fails catastrophically in this case despite the corruption being within expected parameters for a raid6 array.
Of course raid5/raid6 is still problematic on btrfs.
Thank you for the feedback on this.
I can confirm that btrfs is quite reliable when raid1c3 is used for both data and metadata. I believe the result described in README.md is still positive even though I was using raid1 in the format script. It's possible this was a matter of luck!
I will update the scripts to default the metadata raid level to that of RAID_LEVEL, while allowing config override.
I've updated README.md with explorations of both raid6/raid1c3 and raid1c3/raid1c3. I've re-verified these outcomes and included example configs for each to improve reproducibility. Closing this issue.