Maurice Poisson Adriasola wrote:
I intend to backup a host without stopping its services. To achieve it
I've put Debian Sarge's "amdump" in a wrapping bash script that does the
following:
1) Open an ssh connection, as root, to the host to be backed up and run
on it a script that creates and mounts a snapshot of the /var
filesystem.
2) Run Sarge's amdump script
3) Open an ssh connection, as root, to the already backed up host and
run a script that unmounts the snapshot and removes it.
For the time being the only host that has to be backed up is the amanda
server itself. Backups seem to be done right, but once every two runs
the hosts hangs and needs to be rebooted just after doing the backup.
Are you hitting this bug?
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=132057
Because you are snapshotting /var, the oops messages could not make it
to /var/log/messages. But maybe you see something on the console.
When I was testing out lvm2 snapshots, I got bitten by it a few times.
Also there was one installation were it was frequent too, so I removed
snapshots there. Can't test too much on production environments...
I also use software mirroring on that host, and lvm2 has a problem
with that too:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=152162
In my two other installations with lvm2 snapshots (without software
raid1), the bug does not happen. But those both machines happen to be
very quiet during backup anyway. It could be diskactivity related, but
even the /var partition is being snapshotted, and during backup there
really is activity on it, but not much.
Until the bug is solved, I have two other real production environments
still running on lvm1 snapshots with kernel 2.4.18 even.
I never noticed the regularity -- once every two runs -- or is that just
a rough proportion of the crashes/successes?
amcheck is done a couple of hours before amdump. It is also preceded by
snapshot creation and followed by snapshot removal and it never fails,
Thus I believe I must have overlooked something in amanda's
configuration.
Again a clue that it could be load related: during amcheck there is very
little disk activity.
To avoid the trouble with lvm2, I also avoid any conditions like
running out of space, just in case they might tickle the bug.
Maybe you have a larger diskactivity or larger dump or... once every
two runs, tickling the bug?
--
Paul Bijnens, Xplanation Tel +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM Fax +32 16 397.512
http://www.xplanation.com/ email: Paul.Bijnens AT xplanation DOT com
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