Note of caution regarding the use of dynamic memory on Hyper-V

Symptoms

Running a backup with deduplication compression enabled on a virtual machine using the dynamic memory function on Hyper-V may fail with an error due to insufficient memory, or the performance may be extremely slow.

1) Case of Exit -311.
VssStart()
com exception caught(0x8007000e) in VssStart
    :
{IDS_STRING3018}Exit Code: -311

2) Case of Exit -601.
OCB::Cache Name: \?GLOBALROOTDeviceHarddiskVolumeShadowCopyx$AIPMAP
OCB::ReadFile Bitmap Cache 3276800 Level=ERROR [1453]
CD2::Open cache file error: \?GLOBALROOTDeviceHarddiskVolumeShadowCopyx Level=ERROR [1453]
    :
{IDS_STRING3018}Exit Code: -601

Cause

ActiveImage Protector does not support memory expansion at the time of execution backup by the dynamic memory.
ActiveImage Protector recognizes the free memory allocated to the virtual machine at the start of service and attempts to operate within that memory.
Therefore, in environments where large amounts of data and there is an extremely high deduplication rate, executing backup with deduplication compression enabled consumes the physical memory allocated to the virtual machine decreases.
As a result, backup failure due to insufficient memory, or performance may be extremely slow.

Workaround

Change to static memory and set the free space of physical memory to 8 GB or more.

Command to check free memory space.
> typeperf “MemoryAvailable MBytes”

Target Product

– ActiveImage Protector 2016R2 / 2018 Windows Edition
– ActiveImage Protector 4 / 5