On Thu, 2020-12-31 at 13:58 -0700, Chris Murphy wrote: > On Thu, Dec 31, 2020 at 12:18 PM Samuel Sieb <samuel@xxxxxxxx> wrote: > > > > On 12/31/20 4:03 AM, Patrick O'Callaghan wrote: > > > On Wed, 2020-12-30 at 20:16 -0700, Chris Murphy wrote: > > > > Btrfs in a raid1 configuration is significantly different than either > > > > mdadm raid or single disk Btrfs. It will self-heal, unambiguously, > > > > both metadata and data. > > > > > > I currently have mdm RAID1 on two external drives that are used only > > > for backup. They are formatted as ext4. What would be the recommended > > > way to convert them to Brfs RAID1? > > > > Chris can correct me if I'm wrong, but this seems to be the simplest > > method. Remove one of the drives from the array. Format it as btrfs. > > Copy the files from the raid onto it. Add the other drive to btrfs > > configuring it as raid. I can't give you any specific btrfs commands > > though. > > Yeah I'm pretty conservative when it comes to breaking a raid apart > because it is introducing risk by reducing redundancy. I'd say it's > better to get a 3rd drive. But, wie du willst. > > rsync -a /mnt/mdraid/ /mnt/btrfs/ > > Now break the mdraid. Put one of them on a shelf, it can still be used > in degraded mode as an archive. I like using these kinds of broken > raid1 members as long term archives because you really don't want to > write to degraded raids anyway, so there's an added incentive to just > treat it as a read-only archive. > > And the other one: > > btrfs device add /dev/sdXY /mnt/btrfs > btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt/btrfs Thanks. Still haven't done this but here's a follow-up question: My current backup tool is BorgBackup, which does compression and deduplication but took some effort to set up correctly, though it's working now. However it seems that Btrfs can do both these things, so is there a case to be made for just setting it up that way, and using send and receive for the actual copying instead of Borg? It would have the advantage of making the backed-up files a little more accessible without special tools. poc _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
