[Ocfs2-users] Slow umounts on SLES10 patchlevel 3 ocfs2

[Sunil Mushran]

umount is a two step process. First the fs frees the inodes. Then the
o2dlm takes stock of all active resources and migrates ones that are
still in use. This typically takes some time. But I have never heard
of it taking 45 mins.

But I guess it could be if one has a lot of resources. Lets start by
getting a count.

This will dump the number of cluster locks held by the fs.
# for vol in /sys/kernel/debug/ocfs2/*
     do
         count=$(wc -l ${vol}/locking_state | cut -f1 -d' ');
         echo "$(basename ${vol}): ${count} locks" ;
     done;

This will dump the number of lock resources known to the dlm.
# for vol in /sys/kernel/debug/o2dlm/*
     do
         count=$(grep -c "^NAME:" ${vol}/locking_state);
         echo "$(basename ${vol}): ${count} resources" ;
     done;

The debugfs needs to be mounted for this to work.
mount -t debugfs none /sys/kernel/debug

Sunil

On 07/06/2011 08:20 AM, Marc Grimme wrote:
> Hi,
> we are using a SLES10 Patchlevel 3 with 12 Nodes hosting tomcat application servers.
> The cluster was running some time (about 200 days) without problems.
>
> Recently we needed to shutdown the cluster for maintenance and experianced very long times for the umount of the filesystem. It took something like 45 minutes each node and filesystem (12 x 45 minutes shutdown time).
> As a result the planned downtime had to be extended ;-) .
>
> Is there any tuning option or the like to make those umounts faster or is this something we have to live with?
>
> Thanks for your help.
> If you need more information let me know.
>
> Marc.
>
> Some info on the configuration:
> ---------------------------X8-----------------------------------
> # /sbin/modinfo ocfs2
> filename:       /lib/modules/2.6.16.60-0.54.5-smp/kernel/fs/ocfs2/ocfs2.ko
> license:        GPL
> author:         Oracle
> version:        1.4.1-1-SLES
> description:    OCFS2 1.4.1-1-SLES Wed Jul 23 18:33:42 UTC 2008 (build f922955d99ef972235bd0c1fc236c5ddbb368611)
> srcversion:     986DD1EE4F5ABD8A44FF925
> depends:        ocfs2_dlm,jbd,ocfs2_nodemanager
> supported:      yes
> vermagic:       2.6.16.60-0.54.5-smp SMP gcc-4.1
> atix at CAS12:~>  /sbin/modinfo ocfs2_dlm
> filename:       /lib/modules/2.6.16.60-0.54.5-smp/kernel/fs/ocfs2/dlm/ocfs2_dlm.ko
> license:        GPL
> author:         Oracle
> version:        1.4.1-1-SLES
> description:    OCFS2 DLM 1.4.1-1-SLES Wed Jul 23 18:33:42 UTC 2008 (build f922955d99ef972235bd0c1fc236c5ddbb368611)
> srcversion:     16FE87920EA41CA613E6609
> depends:        ocfs2_nodemanager
> supported:      yes
> vermagic:       2.6.16.60-0.54.5-smp SMP gcc-4.1
> parm:           dlm_purge_interval_ms:int
> parm:           dlm_purge_locks_max:int
> # rpm -qa ocfs2*
> ocfs2-tools-1.4.0-0.9.9
> ocfs2console-1.4.0-0.9.9
> ---------------------------X8-----------------------------------
> The kernel version is 2.6.16.60-0.54.5-smp
>
> ______________________________________________________________________________
>
> Marc Grimme
>
> E-Mail: grimme at atix.de