[linux-lvm] Snapshot behavior on classic LVM vs ThinLVM

[Xen]

Xen schreef op 15-04-2017 10:27:

> I created a script to be run as a cron job that will email root in a
> pretty nice message.
> 
> http://www.xenhideout.nl/scripts/snapshot-check.sh.txt

Just was so happy. I guess I can still improve the email, but:


Snapshot linux/root-snap has been unmounted from /srv/root because it 
filled up to a 100%.

Log message:

Apr 17 14:08:38 perfection lvm[463]: Unmounting invalid snapshot 
linux-root--snap from /srv/root.

Earlier messages:

Apr 17 14:08:21 perfection lvm[463]: Snapshot linux-root--snap is now 
96% full.
Apr 17 14:08:01 perfection lvm[463]: Snapshot linux-root--snap is now 
91% full.
Apr 17 14:07:51 perfection lvm[463]: Snapshot linux-root--snap is now 
86% full.
Apr 17 14:07:31 perfection lvm[463]: Snapshot linux-root--snap is now 
81% full.
-------------------------------------------------------------------------------
Apr 14 21:11:01 perfection lvm[463]: Snapshot linux-root--snap is now 
97% full.
Apr 14 21:10:51 perfection lvm[463]: Snapshot linux-root--snap is now 
93% full.
Apr 14 19:25:41 perfection lvm[463]: Snapshot linux-root--snap is now 
86% full.
Apr 14 19:25:31 perfection lvm[463]: Snapshot linux-root--snap is now 
81% full.


I was just upgrading packages hence the snapshot filled up quickly.


System works well. I don't get instant reports but if something happens 
within the space of 5 minutes it is too late anyway.

Only downside is that thin messages get repeated whenever snapshots are 
(re)created. So lvmetad will output new message for me at every 0:00. So 
if thin is > 80%, every day (for me) there is a new message for no 
reason in that sense.