My project has run into problems along these lines as a result of clustering. Since our application servers are managed very strictly by a centralized infrastructure group, we have no guarantees of having the same filesystem available if we have to bring up another server to meet load or balance a failure. In that case, the entire repository gets reindexed over JDBC, which can take quite a while with 15,000 documents.
Of course, I appreciate the performance benefits of having the index locally, but I wonder if there might be a middle ground that could substantially help clustered deployments. Perhaps each server could maintain its own index locally, syncing at intervals with a central datasource. If stored in a protected JCR node, the existing journaling might work to keep things current? Then, if a new repository joins the cluster, it could pull down a ready-to-go index. No idea if this is feasible, of course, just dreaming out loud :) Cheers, Adam Foltzer
