[linux-lvm] backup with snapshots - some principal questions

[Zdenek Kabelac]

Dne 9.12.2015 v 18:52 Stefan Ring napsal(a):
> On Mon, Dec 7, 2015 at 9:05 PM, Lentes, Bernd
> <bernd.lentes at helmholtz-muenchen.de> wrote:
>> What does the message " ext3_orphan_cleanup: deleting unreferenced inode
>> xxxxxx" means ?
>> And it appears always when the script runs.
>
> I'm not entirely sure, but I would guess that these are deleted files
> that were kept alive by some process holding them open at the time the
> snapshot was taken. Since this unreferenced space would be leaked in
> the event of a system crash – and snapshotting behaves essentially
> like a crash –, the log recovery routine cleans them up during mount.

Hi

When lvm2 creates a volume snapshot - it does 2 things during needed suspend,
it's using  'fsfreeze' and it's flushing all bio in process,
so it's not comparable with just a plain crash.

Zdenek