[OpenAFS] Re: Performance issues
Wed, 24 Aug 2011 05:03:20 +0200
Quoting Brandon Allbery <firstname.lastname@example.org>:
> First: is the cache big enough? The working set of even a lightweight
> desktop manager is pretty big.
It's currently set to 128 MB on all of the workstations. I could
increase that, but by how much? I'm under the impression that, not far
beyond this point, the returns tend to diminish.
> Second: AFS is really designed for mostly read-only data. Desktop
> environments are constantly updating the files in ~ so there will be a lot
> of writes.
I'm familiar with the description. But they put so much effort into
supporting user volumes (client caches and all) that I guess I thought
it might do better in this case than I had a right to expect.
> Third: especially with Iceweasel/Firefox, you'll find that it helps a lot
> to symlink the cache into /var/tmp or other fast local storage. ...
Actually, each of our physical servers also runs a Squid proxy cache,
so we decided to simply disable all of the browser caches.
Nevertheless, when someone's user volume is remote, Iceweasel still
runs too slow.
> ... (Desktop environments have caches as well, which again should be
> symlinked to local storage.) ...
Oh, that sounds like it will be worth a little extra performance!
> ... This still won't help with KDE/Gnome-like updating of application
> and system settings when you look at them funny, but it will help a lot.
When we were first setting up this system, we also tested the Gnome
and KDE desktops just for fun. Gnome didn't do too badly with a remote
user volume, but as I expected, KDE (my own favorite desktop) was just