R: [Linux-cluster] Performance tuning help sought

[Bill Sellers]

There are some TCP tuning parameters you can change in the 
/etc/sysctl.conf.  Adding these made a noticeable improvement for us. 
Also, if you use any NFS, set your rsize and wsize = 32768 (NFS mount 
options) in a Linux 2.6 kernel.  The noatime mount option appears to 
work well.  We have abandoned ext3 for filesystems > 1Tb in favor of 
reiserfs and jfs.   These other filesytems appear to give better 
performance in a cluster environment. If you use gfs as the filesystem, 
then the above point is moot.

http://dsd.lbl.gov/TCP-tuning/linux.html

http://www.nren.nasa.gov/tcp_tuning.html

http://nfs.sourceforge.net/nfs-howto/ar01s05.html


Kadlecsik Jozsef wrote:
> On Tue, 4 Mar 2008, Leandro Dardini wrote:
> 
>>> What can we do, besides increasing the RGs size? 
>>> Is there any kernel parameter, which could be tuned (say vm 
>>> parameters)?
>>> Would it help to set higher MTU values for openais? (But how 
>>> could one set it?)
>> To speed up things a little, try mounting your partition without atime 
>> (noatime). This will prevent contention locking on directory.
> 
> It's already done, I forgot to mention.
> 
> Best regards,
> Jozsef
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-- 

Bill Sellers, CISSP
Team Lead/Systems Administrator, ConITS
Sr Systems Analyst, NCI Inc.