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cannot create or extend a volume group, shadowimage fails too.....

somewhere, someone gave too much power to nmon ……. If you noticed that suddenly you cannot do what the topic of this post says check if nmon is running.
Next, kill it and repeat the command(s) that previously failed. Do they work now? I think so.

In the last few months I noticed this on few of our hosts but since I have not patched them I missed to make the connection. Yesterday, my colleague patched our DSMC backup servers to AIX and tonight’s ShadowImage backups failed……

The following output explains everything:

# recreatevg -f -y epcdbm_vg $epcdbm_vg_disk
Method error (/usr/lib/methods/chgdisk):
0514-062 Cannot perform the requested function because the
specified device is busy.
0516-1320 recreatevg: Unable to recreate volume group.

The command fails. I kill nmon

# ps -ef | grep nmon
    root  4587738 11731134   0 11:13:15  pts/2  0:00 grep nmon
    root 10748198        1   0 00:00:01      -  0:02 /usr/bin/topas_nmon  -f -T -d -A -m /var/nmon -s 180 -c 480 -youtput_dir=/var/nmon/tsmdbrpu001 -ystart_time=00:00:00,Jul25,2014
# kill -9 10748198

Let’s try to bring the vg back.

# recreatevg -f -y epcdbm_vg $epcdbm_vg_disk

It worked! Like I said, the same will make extendvg work as well.

To resolve this new issue permanently, I modified my backup scripts as follows. Before I bring the volume groups in, my scripts executes now the following line.

kill -9 `ps -ef | grep nmon | grep -v grep | awk '{print $2}'`

At the end, just before the exist, I start nmon as follows (using the entry from root's own crontab.


Please let me know if you know about any other fix.

Have a good weekend!!!

Posted in Real life AIX.

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2 Responses

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  1. Benoît Créau says

    Hi Mark,

    Got a similar problem and was resolved by this APAR (nmon was locking some devices) :
    No problem after applying the fix.



  2. MarkD:-) says

    Thanks Benoit!!! will download it and patch!

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