[OpenAFS] Re: Afs User volume servers in VM's

Andrew Deason adeason@sinenomine.net
Wed, 26 Oct 2011 09:55:06 -0500

On Wed, 26 Oct 2011 07:34:04 -0700 (PDT)
Booker Bense <bbense@slac.stanford.edu> wrote:

> Ideally, you'd like one mini-server per user volume and at least the
> user would only shoot himself in the foot. I don't think this is
> particularly practical even with current VM's, but how far can you
> push it?

You don't necessarily need VMs for this; at least, I'm not sure I see
what benefit you get from separating these via VMs. You can (with I
think 1.6.0 or a patch to 1.4.x) run these as chrooted fileservers on
the same box, which would have less overhead.

I think you could push it pretty far as far as resource utilization on
the box goes, since the fileserver can scale down pretty small wrt
memory usage. However, keep in mind that in the current implementation
you need one IP per fileserver, which is the resource you may run out of
first unless you have a lot of unused ipv4 space.

This also doesn't help you much if the server is getting bogged down due
to the I/O in servicing the relevant requests, unless you separate the
user volumes physically. But for the simple (and presumably common) case
of running out of fileserver threads or the fileserver not being
mp-scalable, sure.

Andrew Deason