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Q176170: XADM: Single Instance Ratio Counter Indicates Value Less Than 1

Article: Q176170
Product(s): Microsoft Exchange
Version(s): WinNT:4.0,5.0,5.5
Operating System(s): 
Keyword(s): kbusage
Last Modified: 14-MAR-1999

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The information in this article applies to:

- Microsoft Exchange Server, versions 4.0, 5.0, 5.5 
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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 words: perfmon

======================================================================
Keywords          : kbusage 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : WinNT:4.0,5.0,5.5
Issue type        : kbinfo

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