[Linux-cluster] gfs2_tool settune demote_secs

[Kaloyan Kovachev]

On Mon, 12 Oct 2009 11:14:08 +0100, Steven Whitehouse wrote
> Hi,
> 
> On Mon, 2009-10-12 at 13:07 +0300, Kaloyan Kovachev wrote:
> > Hi,
> > 
> > On Fri, 09 Oct 2009 18:01:36 +0100, Steven Whitehouse wrote
> > > Hi,
> > > 
> > > The idea is that is should be self-tuning now, adjusting itself to the
> > > conditions prevailing at the time. If there are any remaining
> > > performance issues though, we'd like to know so that they can be
> > > addressed,
> > > 
> > 
> > I have noticed a possible performance issue while experimenting with
> > ping_pong, but the test is representing normal operation.
> > 
> The ping_pong test uses fcntl() locks. These go through dlm_controld and
> are independent of the filesystem, whether you are using GFS/GFS2 (or
> maybe even OCFS2 now as well). So these are not the same as the glocks
> that the last message was referring to.
> 
> > The setup:
> >  3 node cluster (Node1, Node2 and Node3) with shared GFS2 partition
> > 
> >  1. Starting ping_pong on one of the nodes (Node1) i get several thousands
> > (30k+) of locks per second
> > 
> >  2. Stopping it after a while and immediately starting (moving) it to Node2
> > (just like a shared service resource after failover) the number of locks goes
> > below 2000
> >  Probably because the locks are held on Node1, but then even after hours it
> > does not go back to 30k+ locks per second and stays at <2000
> > 
> >  3. Stopping ping_pong on Node2 and starting it again on the same or another
> > node (Node1 or Node3) after 10-20min there are again 30k+ locks per second
> > 
> >  Not sure if demote_secs would help, because i can't test, but it would be
> > great to have the locks released from Node1 to Node2 after some time at step
> > 2. not 3.
> > 
> What options have you got in your cluster.conf relating to plocks? What
> kernel are you using?
> 

As i am just testing there is still nothing in cluster.conf except the nodes
definition, so they should be the defaults.
The kernel is 2.6.31.1

> Steve.
> 
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