Microsoft KB Archive/833398

= Exchange Mailbox Manager report totals do not match the report details in Exchange 2000 and Exchange 2003 =

Article ID: 833398

Article Last Modified on 10/25/2007

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APPLIES TO


 * Microsoft Exchange 2000 Server Standard Edition
 * Microsoft Exchange Server 2003 Enterprise Edition
 * Microsoft Exchange Server 2003 Standard Edition

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SYMPTOMS
When you use Exchange Mailbox Manager to generate a report for each mailbox that it scans on a computer that is running Microsoft Exchange 2000 Server or Exchange Server 2003, the report totals do not match the report details.

If you sum the number of messages from each mailbox, the amount is not equal to the total number of messages that the summary reports.

If you sum the size of messages that were cleaned from each mailbox to calculate the space freed by Mailbox Manager, the total size of the cleaned messages does not match the total size that the summary reports.



CAUSE
This behavior occurs because the Mailbox Manager scan uses a MAPI interface that does not account for single-instance storage. Therefore, the details that are reported for individual mailboxes are not exact.

Single-instance storage inserts one copy of a message in a database even when the message is sent to more than one recipient on the same server. Both recipients access the single instance of the message to read the message. If this were the only message in the database, the single-instance storage ratio for this database would be 2.

If the message were sent to four people, two on your server and two on another, only a single copy of the message would have to travel to the other server to deliver the message to both users.

Single-instance storage makes sure that only one copy of a message is required on a server, regardless of the number of message recipients.

Keywords: kbprb KB833398

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