My query is one to do with the creation of a single database vs multiple databases in relation to my disk subsystem. I have installed a new iSCSI SAN on which I plan to install an Exchange 2010 virtual machine and migrate all mailboxes from an existing Exchange 2007 server. Unfortunately, I am limited with my disk subsystem in the fact that I only have a single raid 5 array comprising of 7 X 15k SAS disks to house the entire system. This being the case, I feel it is entirely pointless to separate the database(s) and log file(s) onto different virtual disks on the same disk array as this will not provide any performance benefit.
As I have no choice but to have the database(s) and log(s) on the same raid array, my question as mentioned is regarding the creation of a single database vs multiple databases. I am unsure if there is any benefit to creating multiple databases in this scenario and worried it could actually decrease performance. The only benefit I can think of for creating multiple databases is the fact that online defragmentation could complete much quicker for each DB. Our current single DB is around 95GB and the online defrag never has time to complete leaving the performance less than optimal.