After adding more clients to my list, I noticed that I began getting problems with Joomla. Recently I upgraded to Joomla 1.0.14 from Joomla 1.0.13.
I host web sites on two separate servers that are connected by a link. In the case that the server goes down either from a hardware issue or a problem with the Internet line, the other server will pickup without missing a beat! All web space is replicated and database information is replicated.
However, I started to get "Invalid Session" errors when logging into the admin ports for Joomla. After doing some research, everyone was stating to ensure that you have the session data in the php.ini file to use "files" and also have the path writeable to everyone. Of course, the path also needs to exist! Everything checked out fine there.
Well, after more digging, I discovered that this sessiondata folder was stored on the regular drive of each server and was not in a location that allowed for replication. I then updated the path in the php.ini file and created a new directory that existed within the replication partition. Restarted IIS on both servers after updating the files. Now, I see the session files being created and seconds later, transferred and showing up on the other server. No more "Invalid Session" errors with Joomla.
This is something that many other people may have trouble with as well with some of these big-name web hosters. If the data is not replicated immediately and you jump to another server – POOF! You will get "Invalid Session" from your Joomla administration portal when attempting to login.