[Zope] Putting Zope into a tailspin can kill a whole Linux Server

[Oliver Bleutgen]

BZ wrote:

 > This is the second time I have done this and I just thought the list
 >  should know.
 >
 > Once in awhile (every six months or so) I send Zope a request that
 > it just cannot handle. At that point (after waiting for a good five
 >  minutes) I  cancel the request by stopping the browser. This has
 > twice resulted in Zope spinning out of control (taking up more and
 > more CPU) untill it kills  the entire server box.
 >
 > How does it kill a Linux box you say?
 >
 > Well, it kills off Apache, kills off SSH (no more remote access),
 > kills off FTP. They all just become unresponsive.
 >
 > Here are the two times it has happened:
 >
 > - Zope 2.3.2, on RH Linux 7.0 384 MB Ram, 650 MHz Pentium: I tried
 > packing the database, stopped it and tried repacking it.
 >
 > - Zope 2.4.2 (same hardware): I tried creating a VERY LARGE Poll
 > graph (10,000) and stopped it while it got going.
 >
 > I don't know if this is a bug or whatever, but it could be a
 > problem. Zope can certainly be sent into a tailspin.


I am by no means an kernel expert (for whatever os), but it might be
interesting to find out what exactly causes your box stalling. Are you 
sure that you aren't going OOM (out of memory) instead of "overloading"
the cpu? What I mean is that the unresponsivenes(sp?) of your system 
might be caused by something other than zope's cpu-usage, i.e excessive
memory usage.
If you can repeat this, it might be worth using top/and or vmstat
to watch what happens while zope goes to no man's land.

cheers,
oliver