[gpfsug-discuss] CES and NFS Tuning suggestions

[Bryan Banister]

One major issue is the maxFilesToCache and maybe the maxStatCache (though I hear that Linux negates the use of this parameter now?  I don’t quite remember).  Ganesha apparently likes to hold open a large number of files and this means that it will quickly fill up the maxFilesToCache.  When this happens the [gpfsSwapdKproc] process will start to eat up CPU time.  This is the daemon that tries to find a file to evict from the cache when a new file is opened.  This overhead will also hurt performance.

IBM in a PMR we opened suggested setting this to something like 5 Million for the protocol nodes.  I think we started with 1.5 Million.  You have to be mindful of memory requirements on the token servers to handle the total sum of all maxFilesToCache settings from all nodes that mount the file system.

Of course the other, standard NFS tuning parameters for number of threads and NFS client mount options still should be adjusted too.

Hope that helps,
-Bryan

From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Oesterlin, Robert
Sent: Sunday, October 16, 2016 7:06 PM
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Subject: [gpfsug-discuss] CES and NFS Tuning suggestions

Looking for some pointers or suggestions on what I should look at changing in Linux and/or GPFS "mmchconfg" settings to help boost NFS performance. Out of the box it seems "poor".


Bob Oesterlin
Sr Storage Engineer, Nuance HPC Grid
507-269-0413


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