We just did an upgrade to Zope 2.6.2 and ZEO 2 (we were on 2.6.1 and ZEO 1 before). We ended up setting up clients on port 8080 this time, rather than running them on 80 as we did before, but we're using the same round robin Squid load balancing setup we were using previously (from Toby Dickenson's howto here: http://www.zope.org/Members/htrd/howto/squid). What we're noticing, though, is now it looks like changes we make through our rewritten URLs are occurring on one client and not necessarily happening immediately on the other clients. I'm guessing this is a caching issue or something that we didn't have to deal with with ZEO 2, but I'm not sure. I do see these error messages in the log: 2003-10-07T13:40:00 PROBLEM(100) ZCS:25346 Invalidate('\x00\x00\x00\x00\x00\x00\x00\t', '') failed for _db: keys My custom_zodb.py is the basic: import ZEO.ClientStorageStorage=ZEO.ClientStorage.ClientStorage(('xxx.xxx.xxx.x xx',7700)) my startup line for a client looks like so: sudo -u zope /usr/bin/python2 $cwd/z2.py ZOPE_CLIENT=8106 -a xxx.xxx.xxx.xxx -f 8021 -w 8080 -u zope --icp=8081 Any ideas? I've read the docs with ZEO about ClientCache, but I'm not sure I'm grasping the concept entirely. ~