[OpenAFS] OpenAFS Client Optimization

Jeffrey Altman jaltman@secure-endpoints.com
Wed, 17 Jun 2009 10:49:40 -0400

Performance characteristics depend on a variety of things.
The OpenAFS for Windows architecture is based upon an SMB
gateway model.  As a result an inability to pipeline operations
when there is only a single CPU has a significant impact.

The Microsoft SMB redirector has a max throughput of 56/MBs
on 32-bit XP and 64MB/sec on 64-bit Vista.

Throughput on gigabit networks using 1.5.59 with a 32-bit XP dual cpu
system with 1.4.8 file servers:

  (MB/sec)               Crypt On 	Crypt Off
  Write                     3.9            15.7
  Read (uncached)	   15.8            31.0
  Read (cached)            55.3            55.3

Reading a 4GB file will always be larger than the cache size on
32- bit Windows.  For 64-bit Windows you can increase the cache
size to many tens of GBs in size.  If you know you will predominantly
reading very large files in a sequential manner then you can increase
the chunksize used for FetchData/StoreData file server operations.

The performance of your file servers matter.  If they are slow
reading from or writing to disk it is going to slow down the clients

Appendix A of the release notes describes all of the settings
that are available to you to adjust.   The values that are used
by default are appropriate for a random client with long round trip
times and limited bandwidth.

Jeffrey Altman

Claudio Prono wrote:
> Hi to all,
> Someone can help me optimizing OpenAFS for Windows Client side? I have
> now a write rate of about 5000 Kbytes/sec, and a read rate of about 8000
> Kbytes/sec on a large file like 4 Gb. There is any way to increase that
> speed?
> Cordially,
> Claudio Prono.