Enabling Software Tracing for MPIO

Applies To: Windows Server 2008 R2

This section discusses how to enable software trace logging for troubleshooting MPIO issues.

Note

Software trace logs are binary files that are typically only used by Microsoft Technical Support for troubleshooting an issue, and are not directly viewable.

Create a GUID file to enable tracing

You must first create a GUID file by using Notepad. The file must contain the GUID of the provider that corresponds to the driver that you want to trace. For this example the file name is MPIOGUID.CTL. The first line is required for tracing MPIO and the second line is required for tracing the Microsoft DSM, as follows:

{8E9AC05F-13FD-4507-85CD-B47ADC105FF6} 0x0000FFFF 0xF
{DEDADFF5-F99F-4600-B8C9-2D4D9B806B5B} 0x0000FFFF 0xF

The format of the files is as follows:

<GUID of provider to trace><Trace Flag><Trace Level>

Note

The Trace Flag and Trace Level values are typically specified by Microsoft Technical Support, depending on the type of troubleshooting being performed.

Start tracing

To start tracing, type the following at the command prompt:

logman.exe create trace <Name> -ets -nb 16 256 -bs 64 –o <LogFile> -pf <GUID File>

Logman.exe is present in the %windir%\system32 directory. The name <Name> is assigned to that trace session. The trace level is controlled by the value of the flag in the GUID File. <Guid File> contains the trace GUID and the trace flag. The trace messages are written to <Log File>.

For example, to start a trace session named MPIOTrace and create a log file named MPIOTrace.Log, type the following command:

logman.exe create trace MPIOTrace -ets -nb 16 256 -bs 64 -o MPIOTRACE.log -pf MPIOGUID.CTL

Stop tracing

To stop tracing, type the following at the command prompt:

logman.exe stop <Name> -ets

For example, to stop the trace session with the name MPIOTrace, type the following command:

logman.exe stop MPIOTrace -ets

The log file is a binary file. If you are troubleshooting an MPIO issue with Microsoft Technical Support, send the log file to your support representative, who can then use it to analyze the failure.

Query the trace status

To verify that tracing is running properly, type the following at a command prompt:

logman.exe query -ets

To return extended information about the tracing status, type the following at a command prompt:

logman query MPIOTrace -ets