[Zope] Link of the Day

Paul Winkler pw_lists at slinkp.com
Mon Jun 7 09:48:23 EDT 2004


On Mon, Jun 07, 2004 at 11:21:25AM +0200, Bert Vanderbauwhede wrote:
> The only thing I can conclude, is that the problem is caused by requests
> that somehow lock up Zope. These requests come from one or more users
> at the university.

(snip)

Just a guess, but maybe there are some local user(s) who are infected
with worms / virii that are DOSing your Zope?
I'd look through your Zope access log and see if it's only the number
of requests that are a problem, or the 

I've seen on some of my sites that extremely large numbers of requests
to non-existent pages can effectively DOS zope. But I've never
found a solution other than waiting for the storm to subside.
I'd like to do some research on this "if I get time"...

Another guess: Do you use ZEO? Can you see if there were several 
overlapping requests for downloading large files? I found that
this slowed zope so much that no more requests completed until
one or several of the large file requests finally succeeded.
I noticed in the ZEO server log that there were a bunch of cache 
flip messages in quick succession.  My interpretation is that the ZEO 
cache is basically overloaded to the point of being useless, and most/all 
requests are waiting on the very busy ZEO connection.  Things got better 
when I drastically increased the size of the ZEO client cache so that 
no single download could trigger a cache flip.
 
-- 

Paul Winkler
http://www.slinkp.com



More information about the Zope mailing list