20 Tips on Microsoft Hyper-V Dynamic Memory

Over the last week or I published a series of 20 tips on Dynamic Memory on Twitter (@michelroth). Here's the compilation in case you missed it.

Dynamic Memory Tip#1: Dynamic Memory is not supported for Windows XP guests
Dynamic Memory Tip#2: Only Enterprise and Ultimate editions of Windows 7 and Vista are supported guests.
Dynamic Memory Tip#3: If you want demo DM quickly, just set the MSPaint image properties to the maximum size.
Dynamic Memory Tip#4: DM only responds to actual memory allocation requests. It does not respond to memory queries (registry)
Dynamic Memory Tip#5: You need to update both the Hyper-V host AND the guest to use DM for most OSes.
Dynamic Memory Tip#6: You need this hotfix on 2008 SP2 Web and Standard Edition for DM:
Dynamic Memory Tip#7: Easiest way to setup DM: just configure startup memory. Best way: set Maximum memory as well (not 64 GB)
Dynamic Memory Tip#8: Don’t worry if you don’t see DM returning RAM when you close apps. This is by design. Only under heavy load will RAM be reclaimed.
Dynamic Memory Tip#9: For Windows 7 and Windows Server 2008 R2 you only need to install SP1 to enable DM.
Dynamic Memory Tip#10:Almost  always there is no reason to set ‘Memory Priority’ in VDI scenarios.
Dynamic Memory Tip#11: VMs need to be powered of change/enable Startup RAM and Maximum RAM
Dynamic Memory Tip#12: Memory Buffer and Memory Priority can be changed while guest is running.
Dynamic Memory Tip#13: Setting DM on a VM that does not support it will result in the VM ignoring all but the Startup RAM config. This will be the traditional maximum memory.
Dynamic Memory Tip#14: Enlarge the Memory Buffer if you have DM performance problems and have I/O-intensive applications and services.
Dynamic Memory Tip#15: DM is most effective when you determine the RAM needed to just successfully boot and set Startup RAM to that value.
Dynamic Memory Tip#16: If the Hyper-V host is part of a failover cluster, Hyper-V also reserves enough memory to run the failover cluster services.
Dynamic Memory Tip#17:Know that adding a RFX adapter adds a significant amount of RAM. Be sure to review  Startup RAM at that time.
Dynamic Memory Tip#18: Setting Startup RAM too low is bad. Real bad. Your VM will not boot and there is no descriptive message on the VM.
Dynamic Memory Tip#19:When you use DM in a VM, don’t trust Task Manager anymore for the available memory. It only sees the Startup RAM.
Dynamic Memory Tip#20: To gather performance data on DM, you should not use guest tooling. Run perfmon on the host instead.

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