Please note, that database is NOT recommended for session storage. It can be a big performance bottleneck, especially in replicated environments.
For saving sessions, file handler seems to be very effective for most setups, except those situations:
- if performance is an issue, the directory which stores session files can be mounted as tmpfs (ram disk).
- if sharing sessions across multiple webservers is needed (in clustered environments), use memcache for storing session information (tip: you can setup more than one instance of memcache eliminate single point of failure). This method, however, sets a limitation of session size to 64k (this should be enough for most applications)
- don't use NFS for sharing session files between webservers, it does not handle locking correctly and can cause corruption of session data.