Microsoft Exchange Performance Counters

Microsoft Exchange Mailbox Server Active Database Copy IO Latency Requirements counters

The following table shows active database copy input/output (I/O) latency requirements counters. When these values are exceeded, the client experience degrades. For example, users may experience slow system performance and message delivery delays.

Counter Name	Description
Database\Database Page Fault Stalls/sec
MSExchange Database\I/O Database Reads (Attached) Average Latency	Indicates the average time, in milliseconds (ms), to read from the database file.
MSExchange Database\I/O Database Writes (Attached) Average Latency	Indicates the average time, in ms, to write to the database file. This counter isn't a good indicator for client latency because database writes are asynchronous.