The Messaging Server message store contains the user mailboxes for a particular Messaging Server instance. The size of the message store increases as the number of mailboxes, folders, and log files increase.
As you add more users to your system, your disk storage requirements increase. Depending on the number of users your server supports, the message store might require one physical disk or multiple physical disks. Messaging Server enables you an add more stores as needed. One approach to adding more stores is by using storage appliances. See Using NetApp Filers with Sun Java System Messaging Server Message Store for information on how to configure Network Appliance storage appliances with Messaging Server.