[OpenAFS] Poor performance on new ZFS-based file server

[Brian Sebby]

Hello,

I've been getting intermittant reports of slow read performance on a new
AFS file server that I recently set up based on ZFS.  It is using locally
attached disks in a RAID-Z2 (double parity) configuration.  I was wondering
if anyone might be able to provide any ideas for tuning / investigating
the problem.  The slow performance that's been reported seems to be against
a RW volume with no replicas.

Right now, I am using OpenAFS 1.4.4 with the "no fsync" patch.  The
options I'm using for the fileserver are "-nojumbo" and "-nofsync". 
I've also set the ZFS parameters "atime" to "off" and "recordsize"
to "64K" as recommended in Dale Ghent's presentation at the OpenAFS
workshop.

There are a bunch of file server options that I'm not sure if they would
help or not.  Any advice would be appreciated as I'm looking at ZFS-based
file servers for some new file servers I'm setting up, but my experience
so far has been mostly with the OpenAFS 1.2 inode-based file server.


Brian

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Brian Sebby  (sebby@anl.gov)  |  Unix and Operation Services
Phone: +1 630.252.9935        |  Computing and Information Systems
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