Comprehensive Mail Storage is an OU scoped feature of Gmail that ensures all copies sent To or From a user are placed in the appropriate folder in their mailbox.
For Outbound messages, Comprehensive Mail Storage manifests itself by ensuring a copy of all messages sent as a user have a copy in the users' Sent folder.
- Messages sent via IMAP
- Messages sent via SMTP
- Messages sent via smtp-relay.gmail.com
- Messages sent via Gmail web interface
For Inbound messages, Comprehensive Mail Storage manifests itself by ensuring a copy of all messages sent to a user have a copy of the original in the user's Inbox folder. Messages are matched based on the Message-ID
- Messages sent matching Compliance Rules
- Messages sent not matching Compliance Rules