[OpenAFS] poor out of cache behavior on writing

[Garance A Drosihn]

At 5:01 PM -0800 2/16/03, emoy@apple.com wrote:
>nfs             0.120u  21.030s  4:19.47  8.1%
>afs 0.5G cache  0.100u 517.330s 10:49.84 79.6%
>afs 2GB cache   0.060u  20.570s  4:49.58  7.1%
>
>In these tests, I copy a 1 GB file from the client to the server.
>In both NFS and AFS cases, I use the same client and server machines.
>
>Notice that with the 0.5 GB cache, it takes about 2.5x longer to
>copy the file, and consumes almost 80% of the CPU, mostly in system
>time.    The 2 GB cache case is more reasonable, taking just
>slightly longer than NFS.

Notice that your cache is half the size of the file you're trying
to copy.  In the past we at RPI have noticed that AFS performance
is bad if the machine has a cache size that is smaller than a
file you want to work on.

-- 
Garance Alistair Drosehn            =   gad@gilead.netel.rpi.edu
Senior Systems Programmer           or  gad@freebsd.org
Rensselaer Polytechnic Institute    or  drosih@rpi.edu