[Linux-cluster] Weird machine load average when using GFS2

[Juan Ramon Martin Blanco]

Hi all,

I'm having a strange issue with a machine included in a two-node cluster. I
have several gfs2 filesystems that reside on top of clustered logical
volumes in a DAS shared by the two nodes.
In machine 2, each time I mount a gfs2 fs, load is incremented by 1, and
decremented if I umount it. This machine is actually not very loaded, load
should be around 0.1
Machine 1 is not affected, load does not change when I mount/umount

[root at machine2 ~]# gfs2_tool list
253:15 MYCLUSTER:gfs201
253:14 MYCLUSTER:gfs202
253:39 MYCLUSTER:gfs203
253:38 MYCLUSTER:gfs204
253:49 MYCLUSTER:gfs205
253:33 MYCLUSTER:gfs206
253:28 MYCLUSTER:gfs207
253:24 MYCLUSTER:gfs208
253:55 MYCLUSTER:gfs209
[root at machine2 ~]# w
 11:29:51 up 1 day, 23:39,  1 user,  load average: 9,00, 9,00, 8,63
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    x.x.x.x     11:19    0.00s  0.02s  0.00s w

If I umount two of the filesystems:
[root at machine2 ~]# umount /my/mount/point/05
[root at machine2 ~]# umount /my/mount/point/06
[root at machine2 ~]# gfs2_tool list
253:15 MYCLUSTER:gfs201
253:14 MYCLUSTER:gfs202
253:39 MYCLUSTER:gfs203
253:38 MYCLUSTER:gfs204
253:28 MYCLUSTER:gfs207
253:24 MYCLUSTER:gfs208
253:55 MYCLUSTER:gfs209

Load is an average, so waiting a few minutes:
[root at machine2 ~]# w
 11:36:07 up 1 day, 23:45,  1 user,  load average: 7,35, 8,20, 8,41
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    x.x.x.x     11:19    0.00s  0.04s  0.04s -bash

And machine one is not having the same behaviour:
[root at machine1 ~]# w
 11:36:45 up 1 day, 23:37,  9 users,  load average: 0,01, 0,04, 0,14
And it has mounted more filesystems:
[root at machine1 ~]# gfs2_tool list | wc -l
26

Both machines are rhel5.3 with the latest updates applied:
Linux machine1 2.6.18-128.1.1.el5 #1 SMP Mon Jan 26 13:58:24 EST 2009 x86_64
x86_64 x86_64 GNU/Linux
Linux machine2 2.6.18-128.1.1.el5 #1 SMP Mon Jan 26 13:58:24 EST 2009 x86_64
x86_64 x86_64 GNU/Linux
cman-2.0.98-1.el5
lvm2-cluster-2.02.40-7.el5
gfs2-utils-0.1.53-1.el5

Any clue?
Greetings,
Juan Ramón Martín
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