Symptoms
Users may experience IMA Service leaking memory and heap expansion: ImaSrv.exe process consumes more than 100 MB. Sometimes it can be even 500 MB or 1.5 GB.
Cause
Heap expansion (memory leak) results from some components not freeing dynamically allocated heap memory. Over time it results in process growth in memory, slow operation, and eventually application hang or crash.
Resolution
To detect the components responsible for memory leaks, the user should enable an additional runtime diagnostic called user mode stack trace database. If this diagnostic is enabled, an application dump should be generated manually when the IMA Service process has an unusual size.
First, you will probably need to download and install Debugging Tools for Windows from Microsoft to use the gflags.exe utility:
http://www.microsoft.com/whdc/ddk/debugging/default.mspx
Use the following syntax to enable diagnostic:
gflags /i ImaSrv.exe +ust
The command should display:
Current Registry Settings for ImaSrv.exe executable are: 00001000
ust - Create user mode stack trace database
If this diagnostic is enabled, an application dump should be generated manually when the IMA Service process has an unusual size or it constantly grows in size. For the latter case several dumps are necessary, for example, when IMA Service reaches 100 Mb, then 200 Mb and 300 Mb.
To get IMA Service user dump you should use Microsoft userdump.exe tool:
http://support.microsoft.com/kb/241215
If you have x64 system you need to be careful about which version of userdump.exe you use:
http://www.dumpanalysis.org/blog/index.php/2006/10/25/userdumpexe-on-x64/
Once you have the dump(s), the diagnostic should be disabled to avoid performance degradation.
To disable the diagnostic, use the following command:
gflags /i ImaSrv.exe -ust
This command should have the output:
Current Registry Settings for ImaSrv.exe executable are: 00000000
Another way is to use the GUI interface by launching gflags.exe:
Note: You need to restart the IMA Service after enabling or disabling the diagnostic.
To verify that gflags.exe was used correctly, Citrix Technical Support personnel can open the dump in WinDbg.exe and run the command:
0:000> !gflag
Current NtGlobalFlag contents: 0x00001040
hpc - Enable heap parameter checking
ust - Create user mode stack trace database
Note: “hpc” flag is added automatically even if you hasn’t specified it.
If you don’t want to install Debugging Tools for Windows, you can modify the registry directly:
Caution! This fix requires you to edit the registry. Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ImaSrv.exe
You need to create a REG_DWORD value under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\<processname> as follows:
Name: GlobalFlag
Type: REG_DWORD
Value: 0x00001000
More Information
If you need the diagnostics enabled for another application, replace ImaSrv.exe with your application name.
