[Zope] Scaling problems, or something else?

[Paul Winkler]

On Thu, May 10, 2007 at 02:10:40AM +0200, Gaute Amundsen wrote:
> On Wednesday 09 May 2007 16:41, Paul Winkler wrote:
> > On Wed, May 09, 2007 at 12:07:54PM +0200, Gaute Amundsen wrote:
> So there is no other possible limit in a zope instance than IO or CPU?

Well, there's RAM of course.  If you run out and start swapping a lot,
that's a big problem :)

btw, if you haven't come across this yet, I recommend reading
Chris McDonough's "Scaling Zope" presentation. It's a couple years old
but still a very good place to start:
http://www.plope.org/misc/szweb/img0.html

> Something out of Control_Panel/Database/main/manage_activity
>  perhaps?

Very helpful if the trouble is ZODB I/O.  Have a look at the activity
graph and see if you're getting lots of loads... might mean your ZODB
cache is too small and is getting thrashed.

Also, I don't think you've mentioned what sort of app this is.
Is it mostly reads or are there lots of writes?
"Mostly reads" is a lot easier to optimize :)

> Is there a way to get that data out without going through port 8080?

Don't think so. But I've never looked.

> Maybe I wil start logging the responstime directly like that! 
> Hm.. good idea :)

If you need that, the trace log can also tell you exactly what the
response time per request is.

> > - DeadlockDebugger may be informative.
> >   http://www.zope.org/Members/nuxeo/Products/DeadlockDebugger
> >
> Sounds a little drastic on a production server, but it may stil come
> to that..  Ought to test it out on another server I guess.

Definitely test-drive it on a scratch server, but production is where
you really need it :-)

re. trace log:
> That looks interesting, except that it can take 15 minutes or more
> to restart zope when load is at the worst. I could try it outside of
> peak ours I guess.

Yeah, restart during off hours and leave it enabled until you have one
episode of peak load slowdown.


-- 

Paul Winkler
http://www.slinkp.com