[linux-lvm] invalid snapshot with umounted fs

[linux-lvm] invalid snapshot with umounted fs

[Christian Hesse]

[-- Attachment #1: Type: text/plain, Size: 815 bytes --]

Hello everybody,

I have a backup scripts that creates read-only snapshots from my lvm volumes,
then runs rsync on them.

This fails for one of my volumes, mount reports an unknown filesystem on the
snapshot. The only difference compared to my other volumes is the fact that
it is not mounted by default.
Mounting the filesystem fixes the problem, the snapshot is valid when created
from mounted filesystem.

I saw this behavior with lvm2 versions 2.02.116 to 2.02.119. Probably I did
not have this configuration before, so possibly the problem exists even
longer.
-- 
main(a){char*c=/*    Schoene Gruesse                         */"B?IJj;MEH"
"CX:;",b;for(a/*    Chris           get my mail address:    */=0;b=c[a++];)
putchar(b-1/(/*               gcc -o sig sig.c && ./sig    */b/42*2-3)*42);}

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

Re: [linux-lvm] invalid snapshot with umounted fs

[Zdenek Kabelac]

Dne 11.5.2015 v 11:35 Christian Hesse napsal(a):
> Hello everybody,
>
> I have a backup scripts that creates read-only snapshots from my lvm volumes,
> then runs rsync on them.
>
> This fails for one of my volumes, mount reports an unknown filesystem on the
> snapshot. The only difference compared to my other volumes is the fact that
> it is not mounted by default.
> Mounting the filesystem fixes the problem, the snapshot is valid when created
> from mounted filesystem.
>
> I saw this behavior with lvm2 versions 2.02.116 to 2.02.119. Probably I did
> not have this configuration before, so possibly the problem exists even
> longer.

Hi


You would need to probably pass more data with your email as without metadata 
archive it's quite hard to guess what is going on.

rule #1 is - when you snapshot gets overfilled - it's automatically LOST - 
it's made invalid and any filesystem on it becomes unreadable.

rule #2 - configure & use dmeventd  (see lvm.conf thresholds) to avoid this 
situation to happen.

If you see some other bug - open BZ case (for rawhide if you can't match your 
distro) and fill in  all info - kernel  version, LVM metadata,  dmsetup status 
and so on...

Regards

Zdenek