Hi, I guess sharing a same hard disk(using cluster) causes I/O issues (locking,delay in read write) and in mail messaging the files used for sending are receiving are of very small size(especially in kb's).
If you looking for sharing the load of the server, as per my view IMAP proxy like perdition is a good approach. for eg like three front end servers for handling IMAP, POP(use perdition ) and webmail requests , two or three back end severs having the user's home directories. and you can also use clustering for failover also. Regards Gejo
