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MAPI Front End App Pool GC Mode Check


We validate the Garbage Collection (GC) configuration for MSExchangeMapiFrontEndAppPool App Pool if the check is executed against an Exchange 2013 server that is not running the EdgeTransport role.

We check if:

  • The server has a total memory of 21474836480 MB and gcServer.Enabled set to false\ In this case we recommend to enable Server GC.

  • gcServer.Enabled is neither true nor false\ This case should be investigated.

  • gcServer.Enabled is false In this case we're running Workstation GC.\ You could be seeing some GC issues within the MSExchangeMapiFrontEndAppPool App Pool. However, you don't have enough memory installed on the system to recommend switching the GC mode by default without consulting a support professional.

How to fix this:

  1. Go into the file MSExchangeMapiFrontEndAppPool_CLRConfig.config\ You can find the file by running %winDir%\system32\inetSrv\AppCmd.exe list AppPool "MSExchangeMapiFrontEndAppPool" /text:"CLRConfigFile" via cmd.exe\ It should be located here: %ExchangeInstallPath%\bin\MSExchangeMapiFrontEndAppPool_CLRConfig.config
  2. Open the file by using an elevated notepad.exe and change the gcServer Enabled value from false to true
  3. Recycle the MAPI Front End App Pool by running: Restart-WebAppPool MSExchangeMapiFrontEndAppPool via PowerShell or by running:\ %winDir%\system32\inetSrv\AppCmd.exe RECYCLE AppPool "MSExchangeMapiFrontEndAppPool" via cmd.exe

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Additional resources:

Fundamentals of garbage collection

Workstation and server garbage collection