LVM Configuration Recoverability

[Alzhy]

Pardon this Question.. I am not done reading through advanced LVM and IgniteUX... But here's the question nevertheless:

If I have an existing HPUX server that already exists with VG's on it already -- and if I re-install the OS (completely -- no remnants of the old install) -- would I still be able to recover these VG's and mount the filesystems on the LVOLs that were in there? Or configuration copies must always be had on tape, different server or the recovery tape/file?

Just comparing recoverability options as I also am responsible with DR...

[Helen French]

If I understood correcly:

1) If you are talking about LVs in root VG (/dev/vg00), it is not recoverable after doing a cold install (fresh install).

2) If you are talking about recovering LVs in other VGs (vg01, vg02 etc), it is recoverable and mountable, provided you don't erase anything on those disks.

3) Preserving vg configuration map files (vgexport) in tape or another system is most recommended. However, if you don't want to do that you still be able to recover those VGs and LVs (vgscan and vgimport).

[James R. Ferguson]

Hi Nelson:

Creating an Ignite recovery tape ('make_tape_recovery') and then using the tape to reinstall on the same hardware will present no problems. A preview 'vgexport' of all volume groups is done during the creation of the recovery tape. During a recovery session Ignite will attempt to 'vgimport' the volume groups it saw previously. Assuming that the disk devicee files haven't changed due to hardware changes since the server was last ignited (cold-installed) the pv_paths cataloged by Ignite will be correct and the volume groups imported.

In the event that disk pv_paths *do* change, you can manually 'vgimport' your volume groups anyway. Ignite helpfully created map files in the '/etc/lvmconf/' directory and these can be used to correctly name your volume group's logical volumes. Should you need to ascertain which physical disk belong to which volume group, do a preview-mode 'vgscan' ('vgscan -apv') to ascertain the correct relationships. The 'vgscan' output will be grouped according to the VGID found on the LVM headers of the physical devices thus found. Using that infomration, and the map files memntioned above, it is easy to construct the pv_path information to supply to the 'vgimport'.

Regards!

...JRF...

[Alzhy]

Well... my net connection finally got restored to "turbo" mode and so I am able to freely search the forums...

Looks like this is a rather simple thing and VG's are easily recovered...

- create /dev/g directory
- mknod...
....

Really a good site for "transitioning" - but sometimes "Lazy" Admins like me ;-) I'll do my best as well to share as much experience and thoughts to the forum...