[OpenAFS] Re: Tuning the client and server

Andrew Deason adeason@sinenomine.net
Mon, 28 Jan 2013 18:18:09 -0600

On Mon, 28 Jan 2013 15:50:02 -0800
Timothy Balcer <timothy@telmate.com> wrote:

> The files are being not being read after they are written.. its a bulk
> write operation.

Okay, but generally you need to read or stat something in order to
write. If you're creating a new file, you need to at least access the
parent directory. And if you're writing to an existing file, you need to
lookup that file as well.

How many directories are there, containing all of the files you're
writing to? Are you trying to write to files in the same directory when
you do this, or do you jump around to different directories a lot? Are
you creating new files exclusively, or do you write to existing files?

> Thanks or that tip on dcache.. I somehow didn't catch it was for a
> memory cache only...

Well, it can be used for a disk cache, but it only affects the amount of
in-memory dcache entries. I don't think you need to tune that unless you
think you're having performance problems coming from moving dcache
entries from disk to memory. I'm not even sure in what conditions that
would happen... maybe if your working set is very close to your cache
size, and everything stays cached.

Andrew Deason