Performance Monitor Logs are Limited to 2.1 GB of Data

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1
• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SYMPTOMS

Although you create a log file using the Windows NT Performance Monitor utility, the maximum size that the log file can grow to is 2,147,483,648 GB. When the size of a Performance Monitor log reaches this 2.1 gig limitation, the file size counter begins to count down backwards placing a negative sign in front of the number of bytes. Also, the log file is corrupted after it reaches that point.

CAUSE

The Windows NT Performance Monitor utility is not designed to collect more than 2.1 GB of data in a log file.

RESOLUTION

In a future version of Windows NT, the Performance Monitor utility will stop monitoring when it reaches the log file limitation.

For a more concise log file containing only certain counters that you specify, use a utility in the "Windows NT 4.0 Resource Kit" called Performance Data Logger.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.