This is kinda long winded folks, don't say I didn't warn you.
I believe I have solved the "asking for a volume that's NOT in the changer
even when a volume that ought to be usable is in the changer" problem.
I believe this addresses the issue many people have where they want to
restrict bacula to using a tape that's in the changer in preference to other
tapes which are not, even if bacula's recycling algorithm seems to prefer
an "offline" volume.
It's a BASH script that has been written for my environment, but should be
adaptable to any bacula implementation. I'm using mysql, and running on
Bacula v 2.0.3. If you're using sqlite or postgresql, you'll have to change
the "mysql" part of the script and may have to adapt the queries.
I've set up the script to run as an admin job before any real backup jobs run
each day.
Here's the script:
#!/bin/bash
/usr/local/bin/bconsole <<EOF
unmount storage=MyAutochanger
update slots storage=MyAutochanger
mount storage=MyAutochanger
status dir
EOF
## Enable any UseVolumesInChanger volumes that are InChanger
for volname in `mysql bacula<<EOF
SELECT VolumeName AS ""
FROM Media,Pool
WHERE Inchanger=1
AND Media.PoolId=Pool.PoolID
AND Pool.Name='UseVolumesInChanger' ;
EOF
`; do bconsole <<EOF
update volume=$volname enabled=1
EOF
done
## Disable any UseVolumesInChanger volumes that are !InChanger
for volname in `mysql bacula<<EOF
SELECT VolumeName AS ""
FROM Media,Pool
WHERE Inchanger=0
and Media.PoolId=Pool.PoolID
and Pool.Name='UseVolumesInChanger' ;
EOF
`; do bconsole <<EOF
update volume=$volname enabled=0
EOF
done
### End of the script.
First I 'unmount' the autochanger, update the slots and remount the
autochanger. I do this because if I 'update slots' with a tape in the drive
bacula "forgets" that the tape is in the drive and errors can result when it
comes time for a job to run.[1] 'update slots' is so that if non-operators
have changed tapes that bacula will know what's actually in the tape drive.
The 'mount' command is used so bacula will be able to use the autochanger
when jobs run. Finally for this section, a 'status dir' is used to nudge
bacula into pruning appropriate volumes.
The next section runs a mysql query to figure out which volumes meet the
following criteria:
1. They are in the correct pool: "UseVolumesInChanger" in this example.
2. They are in a changer. NOTE: This script doesn't care WHICH changer. I
know such a concern will certainly matter for certain implementations. It
doesn't for mine, as I only have one pool that needs this script and that
pool only ever uses one autochanger.
Then I use the output from that query to update the "Enabled" flag to "1"
(yes) for each volume with bconsole.
The final step, commented with"Disable any...", does sort of the opposite. It
queries the mysql database for any volumes in the UseVolumesInChanger that
are NOT in the changer then uses bconsole to set the "Enabled" flag to "0"
(no).
To test this, I have done the following:
1. Manually switch tapes in the autochanger.
2. Using bconsole, run the admin job which runs the script.
3. Using bconsole, 'status dir' to see if the scheduled job that uses the
UseVolumesInChanger pool is asking for a tape that's in the changer or not.
4. Using bconsole, 'list volumes pool=UseVolumesInChanger' and check output to
verify that any tapes not in the changer are "Enabled" = 0.
5. Repeat steps 1-4 using different tapes to verify proper function.
Note that relatively short volume retention periods must be set or bacula
won't be able to recycle tapes that are in the changer and your 'status dir'
commands might get an "*unknown*" result for the volume requested for a
scheduled job. For my purposes, I've set volume retention for the
UseVolumesInChanger pool to 12 hours, as the job runs every 24 hours and it's
more important that a new backup is made every night than it is that last
night's backup stays on the tape.
With this script managing the disabling of volumes to bacula, whatever tapes
are in the changer for this backup job/pool will be preferred over other
tapes, and I can still use the other slots in the autochanger for volumes
from other pools and other jobs.
If anyone sees any problems with this setup, or perhaps ways it could be
improved, I'd like to hear of them. I hope to have the time this afternoon
to write this up on the bacula WIKI. I'm new to mysql, so if there's a more
elegant way to do the query, I'm all ears, erm... eyes. I think there may be
some "smarter" way to get the right pool without the dual "WHERE
Media.PoolId=Pool.PoolID and Pool.Name='UseVolumesInChanger'" bits.
Maybe I ought to get into python so I can write this script for bacula's
internal python capabilities.
--Tim G.
[1] I think that when bacula has "forgotten" about such a tape, that
the "mount" command would make bacula "remember" the tape that was in the
drive. I might test that someday, but I didn't want to when I thought of it
as I wrote this message. If it does, then the unmount command becomes
superfluous and I can get away with just doing an update slots followed by
mounting the device again. *shrug*
-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
Bacula-users mailing list
Bacula-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bacula-users
