[Zope-dev] What makes Zope twirl?

[Gilles]

Hello,

I am working since a long time with zope and was continuously worried about
a few problems, unfortunately none of them was fixed along the years:

- zserver can not 'recover' busy thread
- log show nothing in case of blocking: log is written when the request is
completed, and the log is not flushed at every request. I don't thing Big-M
will help.
- when all thread are busy there is no way to access zope, even to restart
it.
I try to fix this several year ago (I am not an expert of zserver) with
timeout-socket: no luck
So if you find a solution to avoid the lock, please email me. I just know
the monitoring/restarting solution.
I can just tell that having a very basic zope system seams to help: the one
I speak bellow use Zope + Psyco db adapter product. Nothing else, it run
behind apache and until now I had no blocking situation, that's since 4
months.


The annoying thing about this is when you tell other IT peoples: Zope is
very nice, powerful, free, but there is maybe a stability problem. Then
later on you see thoses guys going for another solution. I am working for
the European-Space-Agency and I can tell that at my site (Italie) there is
only one extranet site Zope powered, made by me, and I promote zope since
years(or zope 1.0). Obviously I am not a good 'promoter'

gilles


----- Original Message -----
From: "Paul Winkler" <pw_lists@slinkp.com>
To: <zope-dev@zope.org>
Sent: Thursday, February 06, 2003 9:24 PM
Subject: [Zope-dev] What makes Zope twirl?


>
>
>
>
> Or: when zope goes into a nonresponsive state,
> what can you do to diagnose the cause?
>
> The even that prompts this question:
>
> Our production system (2 zeo clients) went down today.
> Platform: Linux 2.4, Zope 2.5.1 from source (wo_pcgi),
> Python 2.1.3 from source, running behind Apache
> for one site, and a custom java proxy for another site
> (don't ask). ZServer is not exposed to anything
> except the servers running Apache and the Java proxy.
>
> All the zope processes were still running,
> CPU usage was low (almost nil for python), *
> there was plenty of free physical memory & swap.
> Yet Zope was not responding to requests.
> A look at the access logs revealed that
> zope had not logged anything since the time
> we noticed the outage. Nothing
> unusual before that except AltaVista crawling our site
> (a measly 2 requests / second).
>
> A restart seemed to fix everything, though one
> of the zeo servers went down again (same symptoms)
> about 20 minutes after starting. Restarted it again
> and both servers have been fine for hours now.
>
> This seems to be rare; I haven't seen it before on
> this particular server, but I saw a similar wedge
> on our dev machine about 3 weeks ago.
>
> I've looked at ALL the logs (access log, zeo log,
> zope stdout / stderr log) and found nothing at all
> unusual, just the aforementioned AltaVista crawl
> and a couple of RAM Cache errors from non-pickleable
> objects that I need to dis-associate from the cache.
> But none of this is new.
>
> Is it time for "Big M"? WOuld that give me anything
> useful?
>
>
> * this does not sound like other zope "spins"
> I have heard of, in which python eats 99% CPU
> indefinitely due to (probably) an application error.
> see for example:
> http://www.zopezen.org/Members/zopista/News_Item.2003-01-28.1025
>
>
> --
>
> Paul Winkler
> http://www.slinkp.com
> Look! Up in the sky! It's CAPTAIN STETOSCOPE!
> (random hero from isometric.spaceninja.com)
>
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