LV header recovery

[robert kobs]

We replaced a disk with a larger one some time ago. We did not transfer some old information to the new disk, but now the users want it back and our backup tapes have aged out. The disk has had the LV removed using SAM but nothing else (i.e. VG still defined, etc). Is there any way to nondestructively re-define the LV definition to allow access to the data on the disk?
Thanks

[Andy Monks · Accepted solution]

yes there is, however it might take a few attempts.

If it was the last lvol in the volume group, just doing a lvcreate of a size greater or equal to was it was should do.

If it was in the middle, then you'll have to know the size, but as long as no other lvremoves have been done, again a lvcreate (of the exact size) should work.

none of the lvm command will actually touch the data, so it doesn't matter how many times you attempt this.

What you quite often have to do, is create a fake lvol just so that you can get lvm to create a new lvol where the old one was (this is only if you've deleted a 2 or move lvols).

[robert kobs]

Thanks, that worked. Fortunately, we keep decent records of configurations and I was able to recreate the LV as it was before. Haven't had to do that before so I hesitated to try anything as it was my last shot at recovering the data.
Thanks again.
rpk