[OpenAFS] Vice Partition Effects on Disk I/O

Warren.Yenson@morganstanley.com Warren.Yenson@morganstanley.com
Fri, 7 Sep 2001 12:54:11 -0400 (EDT)

Does anyone have experience with benchmarking the effect of differing
partition sizes with AFS?

We usually use vice partitions with sizes between 8 GB and 20 GB. We
recently built a server with 9 x 34 GB partitions and have seen issues
with slowness.

Typically the symptoms are:

 * "vos listvol -extended" takes an inordinate amount of time to complete
 * high "iowait" percentages under top
 * iostat shows disk response in the 1500-2000 ms range for some bursty

All this despite the fact that this server does not have more data on it
than our other servers (around 10GB per partition), this server has faster
CPU (2x300MHz versus 2x165MHz), and much more memory (1.5GB RAM versus
.5GB) than other AFS servers in that cell.

The disk is a 30disk RAID system, with 5 groups of 5-disk RAID5 sets.

Any suggestions would be appreciated.

              - Warren