The ContentStore Mailbox provides SMTP-based journaling. Journaled messages are sent from any mail server to an external recipient using the SMTP protocol. In this case, the external recipient is a mailbox on the Commvault ContentStore Mail Server (SMTP).
The journaled messages are stored as messages on the ContentStore Mail Server (SMTP). After the messages are archived, you can run a cleanup job to delete the messages from the SMTP server. When journaled messages are restored, they are restored as .eml files.
If the CommServe computer is offline, the ContentStore Mailbox continues to receive messages. The messages are not held in a queue on the Exchange server.