[Linux-cluster] gfs2_tool settune demote_secs

[Kaloyan Kovachev]

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 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.

> Steve.
> 
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