We have an internal TWiki server running 4.0.2 with a really fscked up configuration. The 3 people who have been responsible for getting the server to this state are long gone, and the organization is very sensitive to outages on twiki due to their previous incompetance. Some of the brokenness seems to be related to "customization" of the TWiki code itself.
I've basically been told I can't upgrade TWiki in place. What I can do is setup a new server and migrate things over piecemeal, as things prove stable. So, this is what I'm doing.
I currently have 2 servers, the aforementioned 4.0.2 server and a new 4.2.0 server. The 4.2.0 server has been setup and configured, and I've successfully moved some content to it.
I've nfs mounted the root of each TWiki installation on the other server (read-only), and created symlinks for the webs that don't exist on each server. This seems to work fine, and allows for [[Web.TopicName]] links to work across servers.
I've setup modrewrite rules that look like the following on each server for content that lives on the other server:
RewriteRule ^.bin/view/Web/(.*) http://new-twiki.example.com/bin/view/Web/$1
This all works great, and is in use today pretty successfully.
My last stumbling block is the Main web. Currently I have separate Main webs for each server. Will it cause a problem to merge the data from the 4.2.0 server's Main web into the 4.0.2 server's Main web, and to have the two instances share it? I plan to have the 4.0.2 server have read-write access to this web, while the 4.2.0 server will have read-only access.
Is there any reason that TWiki needs to be able to write to the Main web, or does it do just fine with a read-only Main web that's edited by an older copy of TWiki?