[linux-lvm] lvm2 and external enclosures

[Ron Johnson <ron l johnson cox net>]

Hi,

(The purpose of this "exercise" is to implement a backup strategy.)

I created PVs then an LV on a pair of drives in a USB dual 
enclosure, created the FS, backed up my data, umounted the fs, and 
disconnected/powered down the enclosure.

Upon powering it back up/reconnecting it, I did vgscan, vgchange, 
mount, but got IO and "unable to read superblock" errors.

Rebooting, even with the external drives disconnected, made things 
all better (though I did have to do an lvchange -a y).

***** START ******

# 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


[28722.859373] EXT4-fs: unable to read superblock
[28722.859458] EXT3-fs: unable to read superblock

***** STOP *****

Any thoughts on getting lvm2 to play nice with dynamic devices?

Thanks

--
Scooty Puff, Sr
The Doom-Bringer