The prerequisite to enabling archiving is the installation and configuration of the Zimbra Archiving package on at least one mailbox server. The installation of this package provides the ZCS discovery (also known as cross mailbox) search tool and sets the attributes that allow archiving to be enabled on the Zimbra MTAs.
Archiving is configured on a per account basis. When archiving is enabled for an account, any email from or to that account is forked at the MTA, and a copy of the message is delivered to a predefined archive mailbox. The archiving process is transparent to account users.