Additional pre-reqs needed above and beyond Exchange requirements
.NET Framework 4.5.1 deployed on all Exchange servers with CAS role
If .NET Framework 4.5.1 cannot be installed, a hotfix for .NET Framework 4.5 is required
KB2745583 – Windows Server 2012 Download
KB2745582 – Windows Server 2008 R2 Download
Decreases CPU spent in .NET garbage collector
Benefits Mailbox & multi-role
Enable by installing hotfix and setting regkey:
HKLM\Software\Microsoft\.NETFramework\DisableRetStructPinning (REG_DWORD) = 1
A hotfix is now available for Windows Server 2012
Adds two control codes to determine which node owns the GUM lock and which node(s) is/are stuck