[Linux-cluster] Write Performance Issues with GFS2

[Ramiro Blanco]

Hi,

I have a 4 node cluster running gfs2 on top of a EMC SAN for a while
now, and since couple of months ago we are randomly experiencing heavy
write slowdowns. Write rate goes down from about 30 MB/s to 10 kB/s.
It can affect 1 node or more at the same time. Umount and mount solves
the problem on the affected node, but after some random time (hours,
days) happens again.

Operating system: Centos 5.6 x86_64
Kernel: 2.6.18-238.9.1.el5
Cman: cman-2.0.115-68.el5_6.3
Gfs2-utils: gfs2-utils-0.1.62-28.el5_6.1
3 nodes fibre channel 4gb
1 node on iscsi 1gb


I've read that there's a bug concerning slow writes, but i think that
affects newer kernels, isn't that right? Is there any other bug that
could be the root of this?

Cheers,




-- 
Ramiro Blanco