[ale] Examining pre-existing LVM

[Giulio (lists)]

On Friday 21 March 2008, Jeff Hubbs wrote:
> Well, here's how things are looking now:
>
> # ls /dev/mapper
> control  vg0-aux
> # pvs
>   PV         VG   Fmt  Attr PSize  PFree
>   /dev/sdb1  vg0  lvm2 a-   68.50G     0
>   /dev/sdc1  vg0  lvm2 a-    8.47G     0
>   /dev/sdd1  vg0  lvm2 a-   16.95G     0
>   /dev/sde1  vge  lvm2 a-   16.95G 16.95G
>   /dev/sdf1  vgf  lvm2 a-   16.95G 16.95G
> # vgs
>   VG   #PV #LV #SN Attr   VSize  VFree
>   vg0    3   1   0 wz--n- 93.91G     0
>   vge    1   0   0 wz--n- 16.95G 16.95G
>   vgf    1   0   0 wz--n- 16.95G 16.95G
> # lvs
>   LV   VG   Attr   LSize  Origin Snap%  Move Log Copy%
>   aux  vg0  -wi-ao 93.91G
>
> Anything here referring to "vg0" is a pre-existing LVM arrrangement
> involving a mixture of real drives, as you can see in the pvs
> output. The "problem children" I've created are sde1 and sdf1, the
> two external SCSI drives.  Note that they are in an "all space
> free" state.  As I see my current dilemma, I don't have LVs to go
> any further with.

Jeff,

If the dd of the LVM header does not have any info then things are 
outside any decent advice I can give.

One possibility is to look for the root disk/partition where the disks  
came from (if it is not themselves) and look for the LVM 
configuration backup stored under /etc/lvm/.. .

The LVM howto suggests that fsck may be able to help:
http://tldp.org/HOWTO/html_single/LVM-HOWTO/#recovermetadata

Wish could help more. Now off to run vgcfgbackup on all my LVMs.

Giulio