As you've probably read in my post AppCmd introduction and examples, AppCmd is a very extensive tool to administer Windows Server IIS hosting environments. Therefore, now a bit more about a common error message you might get using Failed Request Tracing (FREB): LOG_FILE_MAX_SIZE_TRUNCATE.
FREB error LOG_FILE_MAX_SIZE_TRUNCATE
If you've set up a Failed Request Tracing - also known as "FREB" - for a website in IIS, and if you've configure FREB with verbose information, a common error message you'll probably get is:
LOG_FILE_MAX_SIZE_TRUNCATE
The maximum size of an FREB log file, in IIS 7+, is 512 KB per default. Once that size is reached, the log file is cut off (truncated) and a message LOG_FILE_MAX_SIZE_TRUNCATE is logged.
Did you know you can easily increase the FREB log file size server wide? The following AppCmd.exe command doubles the size to 1024 KB, or 1 MB:
# increase the maximum size for failed request logs
AppCmd.exe set config /section:sites
-siteDefaults.traceFailedRequestsLogging.maxLogFileSizeKB:1024
or 2 MB:
# increase the maximum size for failed request logsAppCmd.exe set config /section:sites -siteDefaults.traceFailedRequestsLogging.maxLogFileSizeKB:2048
Interesting detail: FREB was first called _F_ailed _R_equest _E_vent _B_uffering, and this is why the acronym doesn't match its name in Windows Server IIS.
When using PowerShell command prompt you may have to quote the command:
C:\Windows\system32\inetsrv\appcmd.exe set config /section:sites /"siteDefaults.traceFailedRequestsLogging.maxLogFileSizeKB:2048"
Verify the configuration change in the IIS Manager GUI:
Install Failed Request Tracing IIS module
Enable IIS Failed Request Tracing.
If you need to install the Failed Request Tracing module in IIS, use Install-WindowsFeature cmdlet and the following command:
Install-WindowsFeature -Name Web-Http-Tracing
Notice the module is called "Web-Http-Tracing". See Install IIS in Windows 11 using PowerShell for additional IIS modules and features.