Just an update: we have now switched back to Red Hat 8 and MySQl for our primary application (the company Intranet/Portal) which we release soon. This combination seems to be far more stable. Although we still have slow-downs when the server is under heavy loads it doesn't crash - it only stops responding for a bit. This seems more like a normal load-balancing/performance issue than stability problems. Our machine is a dual P4 2ghz w/ 1gb RAM and RAID disks. I would recommend that anyone wanting to use Zope stay well away from Red Hat 9, having said I'd like to know which distributions people use for their production systems? We still may be having issues with mxODBC connecting to MS SQL Server in Red Hat 8, but we need to test that a bit more. -----Original Message----- From: Dennis Allison [mailto:allison@sumeru.stanford.EDU] Sent: Friday, 21 November 2003 5:40 PM To: Tim Edwards Cc: 'zope@zope.org' Subject: RE: [Zope] Zope threads dying continuosly Tim-- I've been running Zope and MySQL on RH9 but the system has been very unstable even after we upgraded to the bleeding edge (kernel and glibc), set all the magic parameters, etc. I had been using Pound as a load distributing reverse proxy under RH7.3, but it fails under RH9. I wrote my own reverse proxy modifying Pydirector but it has had its problems, possibly also related to RH9 thread problems. Still, we appear to have had an easy time of it relative to the disasterous problems you see. I run on a Athlon dual processor system, 4GB of memory, and a RAID disk. We use Zope 2.6.2b3 with Python 2.1.3. I'm curious what kind of processor you are using. Is it one of the hyperthreaded Intel P4 machines? Anyhow, the bad experiences with RH9 and the changes Redhat is making to their business model have motivated me to explore other distributions. Over the next few days, I'm planning to move our Zopes onto a new OS, one based on the Gentoo distribution. I trolled for comments a week or three ago and Gentoo got raves from several folks I trust. Moving to a different operating system might be the right thing. If you remain with RH9, you should be running the latest kernel and the latest glibc. You may find it useful to export into the environment LD_ASSUME_KERNEL=2.4.1 MySQL and Zope to turn off the new posix threading library which seems to be the culprit (or one of the culprits). On Fri, 21 Nov 2003, Tim Edwards wrote:

Hmmm... I'll try and explain a bit more about our problems. We found Zope to be generally unstable in that, after a few mins up to an hour or so, Zope would sometimes freeze. Also when multiple people were accessing a Zope application that retreives or modifies data in our MS SQL Server database the Zope server would freeze and have to be restarted - always, not just some of the time.

After installing a glibc update for Red Hat 9 that fixes a problem with Python programs not being able to create threads and specifying the -t option in the Zope start script (yes with 500 threads!) it seemed a lot more stable. Now multiple people can use our database access application without it crashing. As for the 500 threads I have now put it down to 9, however it doesnt seem to make that much of a difference in resources - a ps listing tells us we only ever have the normal 2 z2.py processes open at a time.

I am now running the Zope server in debug mode on a terminal and can see that it occaisionally crashes and automatically restarts iteself. Also if I go into the management interface and click on a ZSQL method it crashes - and then restarts itself. Applications that use those methods still seem to work for some reason. However I cannot get to the management interface page for any ZSQL method in the whole Zope installation.

Thanks

-----Original Message----- From: Dylan Reinhardt [mailto:zope@dylanreinhardt.com] Sent: Friday, 21 November 2003 4:16 PM To: Tim Edwards Cc: 'Zope@zope.org' Subject: RE: [Zope] Zope threads dying continuosly

On Thu, 2003-11-20 at 18:15, Tim Edwards wrote:

...

Thanks for your replies, the original reason I asked is that we are having stability issues with Zope.

Such as...?

...

I have tried it without the demon process, but that doesn't appear to help. I then reenabled the demon process and changed the thread count to 500

500 is a huge number of threads. You should probably stick with single digits until you have a well-formed case for doing otherwise.

HTH,

Dylan

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