I think I've finally nailed down a test case, if anyone is bored and wants to play:
I can't file upstream as RH bugzilla is down at the moment..
S.
On Sat, 2 Feb 2019 at 13:34, Steve Dodd <steved424@xxxxxxxxx> wrote:
Weirdly, I thought I had failed to reproduce this bug, but my auto-scrub job ran this morning (first Sat of month), and I got:03:15:15: Starting scrub of rvg/test ...03:15:15: ... scrub started ...03:18:36: FAILED: 7926656 mismatchesSo I really have no idea what's going on there. I will wade through my bash history and see if I can see what I did last week and what triggered this..S.On Wed, 23 Jan 2019 at 10:46, Steve Dodd <steved424@xxxxxxxxx> wrote:Sorry, user error sent the last email before I'd finished typing, trying again..Hi everyone,
I am experiencing a mystery scrub failure after extending a particular LV which is a raid1 type mirror. I am using Ubuntu 18.04, LVM 2.02.176-4.1ubuntu3, Ubuntu kernel 4.15.0-29-generic. I mentioned this on IRC, thought an email might reach more people and allow me to provide more detail.As far as I can tell, the LV was *not* created with --nosync:# lvs rvg/backups
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
backups rvg rwi-aor--- 96.64G 100.00The only odd thing I tend to do is specify extents for the extension manually, being a bit OCD about on disk segment layouts. Having mined .bash_history, it seems that last time I ran:lvextend -l+2561 rvg/backups /dev/sdc3:20480-23041 /dev/sdb3:80097-82658After that, a lvchange --syncaction check rvg/backups showed a huge number for raid_mismatch_count (seemed roughly consistent with the newly extended portion not being synced), but dumping the actual filesystem with partclone from both legs of the mirror through md5sum showed no inconsistencies; the contents are mostly borg repositories and for good measure I verified the data in those using borg as well - no problems.After a full resync all is well again. This is the second time this happened to me on the same LV (I think - certainly the same VG.)Any clues? Any known bugs fixed recently that might not have made it into Ubuntu 1804? I am trying to reproduce with a test LV but can't. Only other thing I can think might be relevant was that the volume was mounted (but quiescent) at the time.Thanks,Steve
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