ReFS volume using DPM becomes unresponsive

In the case you notice that the ReFS volume for DPM backup storage becomes unresponsive and stalls the entire backup solution Microsoft has provided a fix within July 18 cumulative update (KB4035951) that contains three tunable values that you set in the registry.Important: Before you follow these steps, make sure that you have read and implemented the three registry parameters as described in KB article 4016173. If these don't adequately address any issues that you encounter, do not disable these registry parameters. These parameters and the ones described in this section do not overlap functionally, so they can be used together.This update describes additional registry parameters that help address the latency issues described in the "Symptoms" section. These parameters can be used in any combination. Warning: Serious problems might occur if you change the registry incorrectly by using Registry Editor or by using another method. These problems might require you to reinstall the operating system. Microsoft cannot guarantee that these problems can be resolved. Change the registry at your own risk.
Important

• A restart is required for these parameter changes to take effect.

• These parameters must be set consistently on every node of a failover cluster.

Option 1:
This option disables cached pins, which were a major cause of the large active working set.

Specify the indicated values in the following subkey:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem

• Value Name:  RefsDisableCachedPins

• Set RefsDisableCachedPins = 1

• Value Type: REG_DWORD

Option 2:
This option adds a heuristic to ReFS checkpointing logic, which causes ReFS to checkpoint when the delete queue reach a certain size. IOs are stuck on ReFS because the checkpoint logic would get stuck processing a large delete queue.Specify the indicated values in the following subkey:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem

• Value Name: RefsProcessedDeleteQueueEntryCountThreshold

• Set RefsProcessedDeleteQueueEntryCountThreshold = 2048

• Value Type: REG_DWORD

Note: Setting RefsProcessedDeleteQueueEntryThreshold to lower values causes ReFS to checkpoint more frequently. Set the value to 2048, then reduce the value to 1024, then 512.Option 3:
Large duplicate extents calls introduce latency into the system, as other operations will have to wait until these long-running operations are complete. This option reduces the size of the duplicate extents call.

• Note: DPM will set this registry key change as the default value as part of UR4, which will release within August 2017.

Specify the indicated values in the following subkey:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Configuration\DiskStorage

• Value Name: DuplicateExtentBatchSizeinMB

• Set DuplicateExtentBatchSizeinMB = 100. (Default is 2000 [2GB]. Any value from 1 - 4095 is accepted).

• Value Type: REG_DWORD

Option 4:
This option extends the TimeOutValue.Specify the indicated values in the following subkey:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Disk

• Value Name: TimeOutValue

• Set TimeOutValue (in seconds) = 0x78

• Value Type: REG_DWORD

Note: The default value for TimeOutValue is 0x41 (65 decimal). 0x78 translates to 120 decimal.x
How to set the tunable parameters
Tunable parameters