mta Stored Volume

1.3.6.1.2.1.28.1.1.5

The total volume of messages currently stored in the MTA, measured in kilo-octets. This volume should include all stored data that is logically above the mail transport protocol level. For example, an SMTP-based MTA should use the number of kilo-octets in the message header and body, while an X.400-based MTA would use the number of kilo-octets of P2 data. This includes messages that are awaiting transmission to some other MTA or are waiting for delivery to an end-user or application.