Performance counter thresholds are updated. But, there are some differences from Exchange 2003 Performance Troubleshooting Guide for some reasons.

Database Disks:

  • Average Disk sec/Read (or I/O Database Reads Average Latency): The average should be below 20 ms. Spikes (maximum values) should not be higher than 50 ms.

Transactional Log Disks:

  • Average Disk sec/Read (or I/O Log Reads Average Latency): The average should be below 20 ms. Spikes (maximum values) should not be higher than 50 ms.
  • Average Disk sec/Write (or I/O Log Writes Average Latency): The average should be below 10 ms. Spikes (maximum values) should not be higher than 50 ms.

Here are the latest performance counter thresholds: 

Disk Latency Thresholds Performance Stress Troubleshooting Guide
Data Disk Read Latency (average) 20 ms 20 ms
Data Disk Read Latency (maximum) 50 ms 100 ms 50 ms
Data Disk Write Latency (average) (n/a) 20 ms
Data Disk Write Latency (maximum) 50 ms
Log Disk Read Latency (average) 20 ms 5 ms
Log Disk Read Latency (minimum) 50 ms 50 ms
Log Disk Write Latency (average) 10 ms 10 ms
Log Disk Write Latency (maximum) 50 ms 100 ms 50 ms

Memory & Processor Thresholds Performance/Stress
% Processor Time (maximum) 90%
% Processor Time (average) 80%
Available Memory Bytes (minimum) 50 MB
Page Table Entries (minimum) 5000
Memory Pages Per Sec (average) 100
Pool Nonpaged Bytes (maximum) 75 MB
Pool Paged Bytes (maximum) 180 MB
Database Page Fault Stalls Per Sec (maximum) 0

Reference: Troubleshooting Exchange Server 2003 Performance 

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