[OpenAFS] OpenAFS speed

[Nathan Ward]

Several times I have mentioned this and gotten no useful response that I 
can remember.

I am running OpenAFS on linux machines. Take a look at the context switches 
on the client and the server....

(vmstat 1, look at the "cs" column)

NFS solves this problem by having a fully kernel server and client.

What causes these context switches? I'm not too sure. Is it possible to 
find out? Again, I don't know.  IIRC context switches occur when switching 
from kernel to userland and vice versa. Perhaps with all the reading and 
writing disks (client cache and server datastore), and sending packets over 
the network there are this many context switches..?

People claim that "OpenAFS scales better", sure it definately does, but 
should this mean that it's maximum speed is degraded? I don't see how this 
can be..?

Nathan Ward

On Tue, 24 Jun 2003 16:52:45 +0200 (CEST), Lukas Kubin <kubin@opf.slu.cz> 
wrote:

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> I'm running OpenAFS version 1.2.9-2 (Debian package) on a 2-processor
> machine, where "vicepa" is on RAID5 (Adaptec) container installed. The
> filesystem used is ext3.
> When I try to write one 700 MB large file to AFS, it takes more than 3
> minutes to complete. I tried this both locally (by generating the file
> with "dd" from /dev/zero) and through 100 Mbps network. The result was 
> the
> same.
> Is this normal feature of AFS or do I have to do some tuning?
> Thank you.
>
> lukas
>
> - -- Lukas Kubin
>
> phone: +420596398285
> email: kubin@opf.slu.cz
>
> Information centre
> The School of Business Administration in Karvina
> Silesian University in Opava
> Czech Republic
> http://www.opf.slu.cz
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-- 
Nathan Ward
Esphion Ltd.