Austin S. Hemmelgarn <ahferroin7@xxxxxxxxx> writes: > On 2019-11-27 03:36, Christopher Baines wrote: >> Hey, >> >> I'm using RAID 10, and one of the disks has recently failed [1], and I'm >> seeing plenty of warning and errors in the dmesg output [2]. >> >> What kind of performance should be expected from Btrfs when a disk has >> failed? [3] At the moment, the system seems very slow. One contributing >> factor may be that all the logging that Btrfs is generating is being >> written to the btrfs filesystem that's degraded, probably causing more >> log messages to be produced. >> >> I guess that replacing the failed disk is the long term solution to get >> the filesystem back in to proper operation, but is there anything else >> that can be done to get it back operating until then? >> >> Also, is there anything that can stop btrfs logging so much about the >> failures, now that I know that a disk has failed? > > You can solve both problems by replacing the disc, or if possible, > just removing it from the array. You should, in theory, be able to > convert to regular raid1 and then remove the failed disc, though it > will likely take a while. Given your output below, I'd actually drop > /dev/sdb as well, and look at replacing both with a single 1TB disc > like your other three. > > The issue here is that BTRFS doesn't see the disc as failed, so it > keeps trying to access it. That's what's slowing things down (because > it eventually times out on the access attempt) and why it's logging so > much (because BTRFS logs every IO error it encounters (like it > should)). Thanks for the tips :) I've now remounted the filesystem with the degraded flag. However, I haven't managed to remove the disk from the array yet. $ sudo btrfs filesystem show / Label: none uuid: 620115c7-89c7-4d79-a0bb-4957057d9991 Total devices 6 FS bytes used 1.08TiB devid 1 size 72.70GiB used 72.70GiB path /dev/sda3 devid 2 size 72.70GiB used 72.70GiB path /dev/sdb3 devid 3 size 931.48GiB used 530.73GiB path /dev/sdc devid 4 size 931.48GiB used 530.73GiB path /dev/sdd devid 5 size 931.48GiB used 530.73GiB path /dev/sde *** Some devices missing $ sudo btrfs device delete missing / ERROR: error removing device 'missing': no missing devices found to remove So Btrfs knows at some level that a device is missing, from the output of the first command, but it won't delete the missing device. Am I missing something? Thanks, Chris
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