[OpenAFS] Very large caches

[Cees de Groot]

Hi,

I'm currently (slowly) deploying OpenAFS on our server farm (for the time
being, my hypothesis is that the crashes I reported last week were due to a
broken libafs build - I installed the same kernel version on all machines and
made sure that OpenAFS was compiled against that, no problems so far). We have
a sort of luxury problem in that all our webservers (AFS clients) have 36Gig
SCSI drives, which of course aren't really used when everything but the base
Linux install comes from the file server. I'm planning to move these drivers
to the fileservers later on (when they fill up) and replace them with 9Gig
models, but for the time being that's the size I'm working with on the
clients.

At the moment, because I run reiserfs root filesystems and don't feel like
repartitioning until all lights for OpenAFS are green, I have put a 512mb
cache in a loopback-mounted ext2 filesystem. That works fine, but a question
for best performance: is it useful to have a, say, 18Gb client cache? If so,
do the default cache parameters suffice at that size or is some adjustment
necessary? Website data and executables are relatively static, so I am hoping
to off-load the servers by employing big client caches to an extent that they
can continue to double as database servers while the size of the AFS-provided
filesystem grows and grows...

-- 
Cees de Groot               http://www.cdegroot.com     <cg@cdegroot.com>
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