mod_glusterfs (was Re: [Gluster-devel] Hammering start() calls)

[Sascha Ottolski]

Am Sonntag 13 April 2008 11:09:36 schrieben Sie:
> Sascha Ottolski wrote:
> > if you have the time, you might wanna check the list archive for
> > some posting of mine, which unfortunately doesn't give you a
> > solution, but may convince you that you're not alone :-) In my
> > experiments, I couldn't get much more than 900 requests/second
> > pulled from my cluster (being small image files, 5-50 KB in size).
>
> I'm sorry for the late reply, I've been quite busy the last days. But
> back on topic:
>
> Here it gets interesting, as this doesn't match my experience at all.
>
> I currently cannot prove that serving static files with lighttpd from
> a glusterfs mount is any slower than from a local file system. I can
> serve 20000 (20k) requests per second on a quad core box. Though the
> glusterfs export and mount is currently on the same box.

hmm, do you try many files, or only some? I did my tests with mostly 
random access to more than 10,000 files.

>
> However from tracing lighttpd, it seems that it somehow notices the
> difference and adjusts its behaviour. On a local file system files
> are open()ed for every request, on a glusterfs mount it keeps files
> open until the stat cached expires (1 second).
>
> So serving static files is perfect for me and therefor I don't see
> much reason for mod_glusterfs for lighty currently.
>
> Can you please double check that you have mounted your backend file
> system with noatime, and that you have

I think I did in my test, it's definetely the case on the production 
cluster.

>
> server.stat-cache-engine = "simple"
> server.max-fds           = 100000
>
> in lighttpd.conf?

interesting, I really did almost no tweaking, for neither of the 
webservers I tested.


Cheers,

Sascha