On 28 March 2016 at 05:54, Anand Jain <anand.j...@oracle.com> wrote: > > On 03/26/2016 07:51 PM, Patrik Lundquist wrote: >> >> # btrfs device stats /mnt >> >> [/dev/sde].write_io_errs 11 >> [/dev/sde].read_io_errs 0 >> [/dev/sde].flush_io_errs 2 >> [/dev/sde].corruption_errs 0 >> [/dev/sde].generation_errs 0 >> >> The old counters are back. That's good, but wtf? > > > No. I doubt if they are old counters. The steps above didn't > show old error counts, but since you have created a file > test3 so there will be some write_io_errors, which we don;t > see after the balance. So I doubt if they are old counter > but instead they are new flush errors.
No, /mnt/test3 doesn't generate errors, only 'single' block groups. The old counters seem to be cached somewhere and replace doesn't reset them everywhere. One more time with more device stats and I've upgraded the kernel to Linux debian 4.5.0-trunk-amd64 #1 SMP Debian 4.5-1~exp1 (2016-03-20) x86_64 GNU/Linux # mkfs.btrfs -m raid10 -d raid10 /dev/sdb /dev/sdc /dev/sdd /dev/sde # mount /dev/sdb /mnt; dmesg | tail # touch /mnt/test1; sync; btrfs device usage /mnt Only raid10 profiles. # echo 1 >/sys/block/sde/device/delete; dmesg | tail [ 426.831037] sd 5:0:0:0: [sde] Synchronizing SCSI cache [ 426.831517] sd 5:0:0:0: [sde] Stopping disk [ 426.845199] ata6.00: disabled We lost a disk. # touch /mnt/test2; sync; dmesg | tail [ 467.126471] BTRFS error (device sde): bdev /dev/sde errs: wr 1, rd 0, flush 0, corrupt 0, gen 0 [ 467.127386] BTRFS error (device sde): bdev /dev/sde errs: wr 2, rd 0, flush 0, corrupt 0, gen 0 [ 467.128125] BTRFS error (device sde): bdev /dev/sde errs: wr 3, rd 0, flush 0, corrupt 0, gen 0 [ 467.128640] BTRFS error (device sde): bdev /dev/sde errs: wr 4, rd 0, flush 0, corrupt 0, gen 0 [ 467.129215] BTRFS error (device sde): bdev /dev/sde errs: wr 4, rd 0, flush 1, corrupt 0, gen 0 [ 467.129331] BTRFS warning (device sde): lost page write due to IO error on /dev/sde [ 467.129334] BTRFS error (device sde): bdev /dev/sde errs: wr 5, rd 0, flush 1, corrupt 0, gen 0 [ 467.129420] BTRFS warning (device sde): lost page write due to IO error on /dev/sde [ 467.129422] BTRFS error (device sde): bdev /dev/sde errs: wr 6, rd 0, flush 1, corrupt 0, gen 0 We've got write errors on the lost disk. # btrfs device usage /mnt No 'single' profiles because we haven't remounted yet. # btrfs device stat /mnt [/dev/sde].write_io_errs 6 [/dev/sde].read_io_errs 0 [/dev/sde].flush_io_errs 1 [/dev/sde].corruption_errs 0 [/dev/sde].generation_errs 0 # reboot # wipefs -a /dev/sde; reboot # mount -o degraded /dev/sdb /mnt; dmesg | tail [ 52.876897] BTRFS info (device sdb): allowing degraded mounts [ 52.876901] BTRFS info (device sdb): disk space caching is enabled [ 52.876902] BTRFS: has skinny extents [ 52.878008] BTRFS warning (device sdb): devid 4 uuid 231d7892-3f31-40b5-8dff-baf8fec1a8aa is missing [ 52.879057] BTRFS info (device sdb): bdev (null) errs: wr 6, rd 0, flush 1, corrupt 0, gen 0 # btrfs device usage /mnt Still only raid10 profiles. # btrfs device stat /mnt [(null)].write_io_errs 6 [(null)].read_io_errs 0 [(null)].flush_io_errs 1 [(null)].corruption_errs 0 [(null)].generation_errs 0 /dev/sde is now called "(null)". Print device id instead? E.g. "[devid:4].write_io_errs 6" # touch /mnt/test3; sync; btrfs device usage /mnt /dev/sdb, ID: 1 Device size: 2.00GiB Data,single: 624.00MiB Data,RAID10: 102.38MiB Metadata,RAID10: 102.38MiB System,RAID10: 4.00MiB Unallocated: 1.19GiB /dev/sdc, ID: 2 Device size: 2.00GiB Data,RAID10: 102.38MiB Metadata,RAID10: 102.38MiB System,single: 32.00MiB System,RAID10: 4.00MiB Unallocated: 1.76GiB /dev/sdd, ID: 3 Device size: 2.00GiB Data,RAID10: 102.38MiB Metadata,single: 256.00MiB Metadata,RAID10: 102.38MiB System,RAID10: 4.00MiB Unallocated: 1.55GiB missing, ID: 4 Device size: 0.00B Data,RAID10: 102.38MiB Metadata,RAID10: 102.38MiB System,RAID10: 4.00MiB Unallocated: 1.80GiB Now we've got 'single' profiles on all devices except the missing one. Replace missing device before unmount or get stuck with a read-only filesystem. # btrfs device stat /mnt Same as before. Only old errors on the missing device. # btrfs replace start -B 4 /dev/sde /mnt; dmesg | tail [ 1268.598652] BTRFS info (device sdb): dev_replace from <missing disk> (devid 4) to /dev/sde started [ 1268.615601] BTRFS info (device sdb): dev_replace from <missing disk> (devid 4) to /dev/sde finished # btrfs device stats /mnt [/dev/sde].write_io_errs 0 [/dev/sde].read_io_errs 0 [/dev/sde].flush_io_errs 0 [/dev/sde].corruption_errs 0 [/dev/sde].generation_errs 0 Device "(null)" is back to /dev/sde and the error counts have been reset. # btrfs balance start -dconvert=raid10,soft -mconvert=raid10,soft -sconvert=raid10,soft -vf /mnt; dmesg | tail [ 1460.660739] BTRFS info (device sdb): relocating block group 1198522368 flags 1 [ 1460.667802] BTRFS info (device sdb): relocating block group 1164967936 flags 2 [ 1460.674128] BTRFS info (device sdb): relocating block group 896532480 flags 4 # btrfs device usage /mnt Back to only 'raid10' profiles. # btrfs device stat /dev/sde [/dev/sde].write_io_errs 0 [/dev/sde].read_io_errs 0 [/dev/sde].flush_io_errs 0 [/dev/sde].corruption_errs 0 [/dev/sde].generation_errs 0 No new errors after balance. # umount /mnt; mount /dev/sdb /mnt; dmesg | tail [ 1705.259074] BTRFS info (device sde): disk space caching is enabled [ 1705.259078] BTRFS: has skinny extents [ 1705.261887] BTRFS info (device sde): bdev /dev/sde errs: wr 6, rd 0, flush 1, corrupt 0, gen 0 # btrfs device stat /dev/sde [/dev/sde].write_io_errs 6 [/dev/sde].read_io_errs 0 [/dev/sde].flush_io_errs 1 [/dev/sde].corruption_errs 0 [/dev/sde].generation_errs 0 The old device counters are back! No errors in dmesg since last reboot, so they are definitely old errors. # btrfs device stats -z /dev/sde Give /dev/sde a clean bill of health. Won't warn when mounting again. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
