On Sun, 19 Jul 2009 15:23:48 -0500
Ron Johnson <ron.l.johnson@cox.net> wrote:
...
Well, that didn't work...
If I umount the fs, then power-down the enclosure, and power it back
up, these are the results:
# vgscan
WARNING: Ignoring duplicate config node: filter (seeking filter)
Reading all physical volumes. This may take a while...
/dev/dm-1: read failed after 0 of 4096 at 2000380952576:
Input/output error
/dev/dm-1: read failed after 0 of 4096 at 2000381009920:
Input/output error
/dev/dm-1: read failed after 0 of 4096 at 0: Input/output error
/dev/dm-1: read failed after 0 of 4096 at 4096: Input/output error
/dev/dm-1: read failed after 0 of 4096 at 0: Input/output error
Found volume group "backup_vg" using metadata type lvm2
Found volume group "main_huge_vg" using metadata type lvm2
# vgchange -a y backup_vg
WARNING: Ignoring duplicate config node: filter (seeking filter)
/dev/dm-1: read failed after 0 of 4096 at 0: Input/output error
1 logical volume(s) in volume group "backup_vg" now active
# mount -v /mnt/backups
mount: wrong fs type, bad option, bad superblock on
/dev/mapper/backup_vg-backup_lv,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
[28515.817160] EXT4-fs: unable to read superblock
[28515.817343] EXT3-fs: unable to read superblock
[28722.859373] EXT4-fs: unable to read superblock
[28722.859458] EXT3-fs: unable to read superblock
Reboot and it works fine.
I use lvm on an external USB disk, and I also get those messages ('read
failed after 0 of 4096') when the disk goes offline and then returns.
What seems to work for me is '/etc/init.d/lvm2 stop' followed by
'/etc/init.d/lvm2 start'.