XADM: Single Instance Ratio Counter Indicates Value Less Than 1

• Microsoft Exchange Server, versions 4.0, 5.0, and 5.5 ---------------------------------------------------------------------

SYMPTOMS

Using Performance Monitor in Microsoft Windows NT, an administrator can monitor the Single Instance Ratio counter for the MSExchangeIS Private and MSExchangeIS Public objects. This value may sometimes show a number between 0 and 1, which can give the impression of a problem with the information store.

CAUSE

This value represents an approximation of the average instances of every message in the store. Because Microsoft Exchange supports single instances of messages that can be shared by multiple mailboxes, it is possible to have more than one message shared by many users as long as the message remains unaltered and resides in the server store.

However, this value may sometimes show a number less than 1 because of the way the algorithm is designed to work and the way messages are internally tracked by the store. A value of less than 1 should be interpreted as close to 1.

Additional query word: perfmon

Keywords          : XADM kbusage
Version           : WinNT:4.0,5.0,5.5
Platform          : WINDOWS
Issue type        : kbinfo