Server 2025 ReFS Dedup job consumes all memory and hangs server

Question

Hi!

Server 2025 with Hyper-V role and a couple of guests.

Got a 12TB volume with ReFS. 10TB allocated.

ReFS debup was enabled with this:

Enable-ReFSDedup -Volume L: -Type Dedup

But starting a job that do a dedup consumes all memory and ends up hanging the server.

This is after starting the job. And before it hangs the server I stopped it (a little before it exhaust the memory). But if I let it run everything comes to a halt and process start failing because of lack of memory.

Start-ReFSDedupJob -Volume L: -CpuPercentage 30
Stop-ReFSDedupJob -Volume L:

How can I limit the dedup process to work with "what it have" in memory and not taking down the server?

Get-Volume -DriveLetter L | fl
ObjectId             : {1}\\HV\root/Microsoft/Windows/Storage/Providers_v2\WSP_Volume.ObjectId="{baef148e-8ffc-11eb-a21e-806e6f6e6963}:VO:\\?\Volume{4385d
                       0fb-a232-444c-a2e0-8a7f06507baa}\"
PassThroughClass     :
PassThroughIds       :
PassThroughNamespace :
PassThroughServer    :
UniqueId             : \\?\Volume{4385d0fb-a232-444c-a2e0-8a7f06507baa}\
AllocationUnitSize   : 4096
DedupMode            : Disabled
DriveLetter          : L
DriveType            : Fixed
FileSystem           : ReFS
FileSystemLabel      : p02v03sim-ded
FileSystemType       : ReFS
HealthStatus         : Healthy
OperationalStatus    : OK
Path                 : \\?\Volume{4385d0fb-a232-444c-a2e0-8a7f06507baa}\
ReFSDedupMode        : Dedup
Size                 : 13194072424448
SizeRemaining        : 1460263964672
PSComputerName       :

Get-ReFSDedupStatus L: | fl
Volume           : L:
Enabled          : True
Type             : Dedup
Status           : Dedup Cancelled
Used             : 10,67 TiB
Deduped          : 45,7 GiB
ScannedOnLastRun : 11,07 GiB
DedupedOnLastRun : 953,93 MiB
FullRun          : False
LastRunTime      : 2025-02-20 13:32:22
LastRunDuration  : 01m:09.681s
NextRunTime      : N/A