When a message is delivered into the Sun Message Store, a reference is created in the Inbox of each of the message recipients. The reference points to the stored message. As each recipient reads, deletes, and removes (expunges) the message via their respective mail clients, the associated reference to the message is removed. When all references are removed, the message can be purged from the Sun Message Store.
The purge utility removes messages no longer referenced from any user or shared folder and returns the space to the Sun Message Store file system. The purge utility removes unreferenced messages starting with mail two days old and older. It does not remove unreferenced messages in today's and yesterday's mail. You must use the purge utility periodically; otherwise, the size of the Sun Message Store will grow unbounded.
For information on the other maintenance utilities with which purge can run concurrently, refer to TABLE 7-3.
You can invoke the purge utility by issuing the impurge command (see to SIMS Reference Manual and "To Configure the Purge Schedule" on page 160), or you can configure purge options and a purge schedule using the Admin Console.