[linux-lvm] Lvm hangs when creating a snapshot

[Zurell, Falko]

Hello list,

I got a strange problem with lvm on CentOS (free port of redhat enterprise linux). I created a shell script which should create a snapshot of a lvm logical device mounted on /opt. The command works fine when I call it from the shell. I installed the script as cronjob for nightly backup. But then I noticed that the lvcreate of the snapshot hangs when called via the cron. 
I can't kill this process, even not with kill -9 as root. I looked with strace into this process and it does nothing. The opt-filesystem then totally hangs and other lvm operations as well. I even can't reboot the machine normally because unmounting of lvm volumes fail. The only chance is a hard powerdown.
After reboot I can see, that the snapshot was created and can remove it as it is invalid by then.

Unfortunatly I don't have any detailed diagnostic information as every lvm command hangs then.

Is there any way to track down this problem and maybe a solution other then powerdown?

Thanks and kind regards


Falko Zurell

Head of Application Management
falko.zurell at idmedia.com
Mobil +49 (0)176 - 12 594 723

/i-d media AG
Ohlauer Straße 43
D-10999 Berlin

Tel +49 (0)30 - 2 59 47 - 357
Fax +49 (0)30 - 2 59 47 - 471
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