[OpenAFS] Re: bonnie++ on OpenAFS

Andrew Deason adeason@sinenomine.net
Mon, 22 Nov 2010 14:15:30 -0500

On Mon, 22 Nov 2010 20:01:31 +0100
Achim Gsell <achim.gsell@psi.ch> wrote:

> > If the latter (or regardless), I'd try increasing the size
> > of the cache; since you're seeing traffic across the network, I'd
> > suspect you're thrashing.
> Trashing? Mmh. I can write 8 1 GB in parallel with dd without problems
> ...

Are you sure the access pattern for that is the same as the bonnie++
test that's running?

I mean, if it's writing to random places in these files, for example,
your working set is somewhere closer to 8G, and you have a cache that is
1G, well...

> I will store a network dump in my public AFS directory and tell you as
> soon as I have it - may take some time ...

Before you do this, take a look at 'xstat_cm_test <client> -collID 2
-onceonly' (again before/after to be on the safe side), specifically at
the hits vs misses, and the numbers for FetchData, FetchStatus, and
StoreData, which will give some information about how you're using the
cache and how much you're hitting the server.

(If you want to show the data here, putting it in public AFS or a
pastebin may be nice to the other list denizens)

Andrew Deason