[drbd-mc] Lots of pvdisplay commands -> RA timeouts

Rasto Levrinc rasto.levrinc at gmail.com
Mon Dec 17 16:09:25 CET 2012


On Mon, Dec 17, 2012 at 3:39 PM, Caspar Smit <c.smit at truebit.nl> wrote:
> 2012/12/17 Rasto Levrinc <rasto.levrinc at gmail.com>
>>
>> On Mon, Dec 17, 2012 at 3:09 PM, Caspar Smit <c.smit at truebit.nl> wrote:
>> > Hi Rasto,
>> >
>> > I noticed this in one of my clusters:
>> >
>> ...
>>
>> > /usr/local/bin/lcmc-gui-helper-1.4.2 hw-info-daemon
>> > root      9869  0.0  0.0  39856  1516 pts/7    S+   14:49   0:00
>> > \_ sudo -E -p DRBD MC sudo pwd:  /usr/local/bin/lcmc-gui-helper-1.4.2
>> > hw-info-daemon
>> > root      9870  0.3  0.0  27676  5000 pts/7    S+   14:49   0:00
>> > \_ /usr/bin/perl /usr/local/bin/lcmc-gui-helper-1.4.2 hw-info-daemon
>> > root     18176  0.0  0.0   9060  1180 pts/7    S+   14:50   0:00
>> > \_ sh -c /sbin/pvdisplay -C --noheadings -o pv_name,vg_name 2>/dev/null
>> > root     18177  0.0  0.0  17872  1604 pts/7    D+   14:50   0:00
>> > \_ /sbin/pvdisplay -C --noheadings -o pv_name,vg_name
>> >
>> > Why is LCMC running so many pvdisplay commands at once?
>>
>> Hi Caspar,
>>
>> it is running it once in 10 seconds, to see if something has changed.
>> Can you check what does it do on your nodes?
>>
>>  /sbin/pvdisplay -C --noheadings -o pv_name,vg_name
>>
>> Rasto
>>
>
> # /sbin/pvdisplay -C --noheadings -o pv_name,vg_name
>   /dev/sdb   single_array3
>   /dev/sdc   single_array3
>   /dev/sdd   single_array3
>   /dev/sdh   replicated_array1and2
>   /dev/sdi   replicated_array1and2
>   /dev/sdj   replicated_array1and2
>   /dev/sdk   replicated_array1and2
>
> I know that LCMC does monitor changes with the lcmc-gui-helper script, but I
> presume the "hw-info-daemon" part has to run only once and not 5(+) times
> concurrently?
>
> Running 5x pvdisplay concurrently can really slow things down.

It shouldn't run this 5x concurrently. What here probably happens, is that
the hw daemon takes too long and is assumed dead and is restarted.

Can it be that /sbin/pvdisplay -C --noheadings -o pv_name,vg_name
hangs on or takes very long on your system, at least sometimes?

Anyway I can/should fix LCMC to deal with this situation.

Rasto

-- 
Dipl.-Ing. Rastislav Levrinc
rasto.levrinc at gmail.com
Linux Cluster Management Console
http://lcmc.sf.net/


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