Nothing to add but the usual caveats: https://raid.wiki.kernel.org/index.php/Timeout_Mismatch
I use udev for that instead of init scripts. Concept is the same though, you want SCT ERC time to be shorter than kernel's command timer. The btrfsmaintenance package has a scrub.timer that you can configure and enable. It's sufficient to scrub once a month or two, but doesn't hurt to do it more often. There is a nagios btrfs plugin somewhere for monitoring. Otherwise something that parses 'btrfs device stats' for value changes would also work. A rather different thing about Btrfs compared to mdadm raid, is there's no concept of faulty drives, i.e. btrfs doesn't "kick" drives out. Since it can unambiguously know if any block is corrupt or not, it keeps a pesky failing drive in, and just complains (a lot) about the bad blocks while using the good blocks. Device replacement should use 'btrfs replace' rather than 'btrfs device add/remove'. More info in 'man mkfs.btrfs' and 'man 5 btrfs'. It's possible to simulate various problems with loop devices or in a VM. A fun one is setting up dm-flakey for one of the mirrors. A bit easier to chew off is to compile btrfs-corrupt-block.c from btrfs-progs source (it is not included in the btrfs-progs package in Fedora) which has various options for corrupting data and metadata, ability to choose which copy gets the damage, etc. It can be surprising how verbose btrfs is with just one data block is corrupt, when shared among multiple snapshots. It'll tell you about all of the instances of the files sharing that one bad block. -- Chris Murphy _______________________________________________ users mailing list -- users@lists.fedoraproject.org To unsubscribe send an email to users-le...@lists.fedoraproject.org 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@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
