Hello After many searches I’m stuck on several problems, I hope you guys can help me :) I’m using Plone as institutional webportal (Zope 2.9.8-final, python 2.4.4) with python 2.4.4. The portal runs a zeocluster with 4 production instances, 3 threads each, and 1 admin instance (in debug mode). All instances share the same ZODB and data.fs on local drive. We use Apache 2 and a "STICKY_ROUTE" cookie to redirect user to the instance he's logged to. We use SSO authentification (CAS) with PloneCASLogin 2.5.0. Apache configuration: ## Default Virtual Host Configuration Listen xxx.xxx.xxx:80 NameVirtualHost xxx.xxx.xxx:80 <VirtualHost xxx.xxx.xxx:80> ServerName xxx.xxx.xxx ServerAdmin xxx@xxx.xxx <Proxy balancer://lb> BalancerMember http://xxx.xxx.xxx:8080 route=8080" BalancerMember http://xxx.xxx.xxx:8081 route=8081" BalancerMember http://xxx.xxx.xxx:8082 route=8082" BalancerMember http://xxx.xxx.xxx:8083 route=8083" </Proxy> # conditional proxy pass ProxyPass / balancer://lb/VirtualHostBase/http/xxx.xxx.xxx: 80/plone/VirtualHostRoot/ stickysession=STICKY_ROUTE #LOGS #LogLevel debug ServerAlias * CustomLog /opt/apache2/xxx.xxx.xxx.log combined </VirtualHost> We noticed that, sometimes, users are not redirected to right instance, so we decided to use the same temporary_folder for all instances and users are connected to the 4 instances at same time. But this modification causes errors like this one from my event.log file: 2008-11-26T10:45:23 INFO ZPublisher.Conflict ConflictError at / VirtualHostBase/http/XXXXX.fr:80/XXXX/VirtualHostRoot/Cours/ Cours.XXXXX.4424/fichiersan_XXXXX.2530/cours_supports_affichage: database conflict error (oid 0x2571, class BTrees._OOBTree.OOBTree, serial this txn started with 0x037a24a416ae79bb 2008-11-26 09:40:05.315987, serial currently committed 0x037a24a95ee0d788 2008-11-26 09:45:22.237099) (1 conflicts (0 unresolved) since startup at Wed Nov 26 10:43:19 2008) and this one from plone's error_log: Request URL http://XXXXXX.fr/Members/XXXXX/Cours/Cours.XXXXX.4648/cours_attacher_templat... Exception Type database conflict error (oid 0x1247, class BTrees._OOBTree.OOBTree, serial this txn started with 0x037a1ffe66682b66 2008-11-25 13:50:24.001620, serial currently committed 0x037a1ffeae62ca44 2008-11-25 13:50:40.871695) Exception Value database conflict error (oid 0x1247, class BTrees._OOBTree.OOBTree, serial this txn started with 0x037a1ffe66682b66 2008-11-25 13:50:24.001620, serial currently committed 0x037a1ffeae62ca44 2008-11-25 13:50:40.871695) Traceback (innermost last): * Module Zope2.App.startup, line 173, in zpublisher_exception_hook * Module ZPublisher.Publish, line 121, in publish * Module Zope2.App.startup, line 240, in commit * Module transaction._manager, line 96, in commit * Module transaction._transaction, line 380, in commit * Module transaction._transaction, line 378, in commit * Module transaction._transaction, line 436, in _commitResources * Module ZODB.Connection, line 665, in tpc_vote * Module ZEO.ClientStorage, line 893, in tpc_vote * Module ZEO.ClientStorage, line 877, in _check_serials ConflictError: database conflict error (oid 0x1247, class BTrees._OOBTree.OOBTree, serial this txn started with 0x037a1ffe66682b66 2008-11-25 13:50:24.001620, serial currently committed 0x037a1ffeae62ca44 2008-11-25 13:50:40.871695) From what I understand, there's a conflict in my database when user wants to access an object. I assume it's related to the temporary_folder sharing modification because errors appeared after it. Is there a way to resolve this error? Is there inconvenient to share temporary_folder? Should I stop it? My second problem, found in the event.log: 2008-11-26T10:45:28 ERROR PortalTransforms Cannot register transform lynx_dump, using BrokenTransform: Error Unable to find binary "lynx" in /opt/local/bin:/usr/bin:/bin:/usr/ sbin:/sbin:/usr/local/bin:/usr/X11/bin I don't understand when and why Plone tries to access to Lynx. We don't receive any traceback error in Plone's error_log. Last but not least. Sometimes instances stops all alone. We were not able to find why because we don't receive any error, message or signal. When stops occur, we restart Zeo by ssh, then instances works fine for some times but the problem comes back later. The server has 8 processors with very low usage but the 12gb RAM are always saturated à 98%. Python process takes 1 to 2gb RAM but there's a lot of "httpd" processes, up to 2.5gb each, their origin remains unknown to us. Thanks