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It's fine for single a single disk or something that presents as a single disk, like a SAN. RAID1 seems fine also. I really wanted to love it, but after it ate

It's fine for single a single disk or something that presents as a single disk, like a SAN. RAID1 seems fine also. I really wanted to love it, but after it ate my data a couple of times, I gave up trying to use it for mass storage. At that time they didn't have warnings in the documentation and had stated that RAID5/6 were basically complete. I found using mirrored vdevs in ZFS much easier to manage and much more stable.

wtallis 3y ago
> I found using mirrored vdevs in ZFS much easier to manage and much more stable. That's not exactly a fair comparison. If you restricted your usage of btrfs to a similarly narrow range of features, you would probably have had a much better experience.
creatonez 3y ago
RAID1 in Btrfs is not entirely fine. It won't nuke your data and there is no write-hole issue, but if a disk fails you'll have to go into a read-only mode during the rebuild and deal with various hurdles in getting it rebuilt.
- wtallis 3y ago
  > but if a disk fails you'll have to go into a read-only mode during the rebuild and deal with various hurdles in getting it rebuilt. I can't say for sure that this never happens, but that's certainly not been the failure mode for any of the drive failures my btrfs RAID1 has experienced. I don't think I've ever needed to reboot or even remount my filesystem, just replace the failed drive (physically, then in software). But I always have more than two drives in the filesystem, so a single drive failure only puts a fraction of my data at risk, not everything.
- viraptor 3y ago
  > if a disk fails you'll have to go into a read-only mode during the rebuild That's not correct, you can rebuild online. The readonly mode is only relevant when you reboot during the failure and don't have the right options set on the volume. But you totally can replace a live drive without affecting the availability.

wtallis 3y ago

> I found using mirrored vdevs in ZFS much easier to manage and much more stable. That's not exactly a fair comparison. If you restricted your usage of btrfs to a similarly narrow range of features, you would probably have had a much better experience.

creatonez 3y ago

RAID1 in Btrfs is not entirely fine. It won't nuke your data and there is no write-hole issue, but if a disk fails you'll have to go into a read-only mode during the rebuild and deal with various hurdles in getting it rebuilt.

wtallis 3y ago
> but if a disk fails you'll have to go into a read-only mode during the rebuild and deal with various hurdles in getting it rebuilt. I can't say for sure that this never happens, but that's certainly not been the failure mode for any of the drive failures my btrfs RAID1 has experienced. I don't think I've ever needed to reboot or even remount my filesystem, just replace the failed drive (physically, then in software). But I always have more than two drives in the filesystem, so a single drive failure only puts a fraction of my data at risk, not everything.
viraptor 3y ago
> if a disk fails you'll have to go into a read-only mode during the rebuild That's not correct, you can rebuild online. The readonly mode is only relevant when you reboot during the failure and don't have the right options set on the volume. But you totally can replace a live drive without affecting the availability.