I was just experimenting with snapshots in LVM on Ubuntu 12.10. I created a snapshot logical volume of 6.5 GiB, and after making some changes to the origin decided to merge the snapshot back in to undo them. All seemed to be going well, but I noticed several LVM-related segfault messages in syslog.
sudo lvcreate -L6.5G -n backup_snapshot -s /dev/mapper/vg0-backup # made some miscellaneous writes sudo lvconvert --merge /dev/vg0/backup_snapshot sudo umount /snapshot/backup sudo umount /backup sudo lvchange -an /dev/vg0/backup sudo lvchange -ay /dev/vg0/backup sudo mount /backup
Apr 12 04:57:10 bournemouth kernel: [ 5260.813253] EXT4-fs (dm-1): mounted filesystem with ordered data mode. Opts: errors=remount-ro Apr 12 05:00:11 bournemouth kernel: [ 5441.841401] EXT4-fs (dm-5): mounted filesystem with ordered data mode. Opts: errors=remount-ro Apr 12 05:02:00 bournemouth kernel: [ 5551.438487] show_signal_msg: 48 callbacks suppressed Apr 12 05:02:00 bournemouth kernel: [ 5551.438495] lvm: segfault at 28 ip 000000000047f319 sp 00007fff60873de0 error 4 in lvm[400000+d9000] Apr 12 05:02:01 bournemouth kernel: [ 5552.458797] lvchange: segfault at 28 ip 000000000047f319 sp 00007fff935f4380 error 4 in lvm[400000+d9000]
I then unmounted the origin LV, made sure the snapshot no longer existed, and ran
fsck.ext4 -f on it; it checked out OK that way. But I'm still worried about the segfaults. Is it possible my data got messed up in some way that fsck wouldn't catch? The volume I was experimenting with was a backup one, and all the filesystems I have backed up on it are still in working order, so I could just start over and back them up again. But on the other hand, I'd like to keep my incremental backup history. I'd just like reassurance that I can trust these backups.