Server 2025 - high CPU and RAM

[pfeifix]

The ReFS memory exhaustion fix is expected from Microsoft in July for HCI23H2 and Windows Server 2025.

Any confirmation the fix is contained in July's cumulative update (KB5056579)?

[DaStivi]

i asked for update in my MS Premiere Case, as soon as the fix is released publicly and i haven't heard anything yet... and statement was that the release was planed more in august then in july... see a few post back from me...

[karsten123]

any news?

[ReKe]

Looks like the fix for Server 2025 could come next month. The actual Preview for Windows 11 shows the fix.

[File system] Fixed: This update addresses an issue in the Resilient File System (ReFS) where using backup applications on large files could occasionally result in system memory becoming fully exhausted.

https://support.microsoft.com/en-us/top ... df6bbfe9c3

[JTT]

Just got the same update from MS: I just wanted to provide you with a quick update regarding the ongoing ReFS issue

Our Product Group team has shared July 22, 2025—KB5062660 (OS Build 26100.4770) Preview - Microsoft Support for you to install on your affected server.
https://support.microsoft.com/en-us/top ... df6bbfe9c3

[karsten123]

did you install the update and does it fix the issue?

[JTT]

Yes, i installed it. On the positive side, the main issue with high disk usage spikes seems resolved. I´ll try to monitor the server. Also usually after restart, RAM usage went up, but now it seems also normal.

[karsten123]

sounds promising. fingers crossed

[obengert]

We have also installed the patch on Monday, which is still listed as 'preview'
Hotfix(s) Installed.
....
KB5062660

But had a BSOD yesterday again.

Yes, i installed it. On the positive side, the main issue with high disk usage spikes seems resolved. I´ll try to monitor the server. Also usually after restart, RAM usage went up, but now it seems also normal.

Did you also apply any registry keys?

[JTT]

Yes i have those registrys keys:

I made these changes, along with the patch.

$regPath = "HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem"

New-ItemProperty -Path $regPath -Name RefsEnableLargeWorkingSetTrim -PropertyType DWord -Value 1 -Force
New-ItemProperty -Path $regPath -Name RefsNumberOfChunksToTrim -PropertyType DWord -Value 32 -Force
New-ItemProperty -Path $regPath -Name RefsDisableCachedPins -PropertyType DWord -Value 1 -Force
New-ItemProperty -Path $regPath -Name RefsProcessedDeleteQueueEntryCountThreshold -PropertyType DWord -Value 512 -Force

fsutil behavior set DisableDeleteNotify ReFS 1

New-ItemProperty -Path "HKLM:\SOFTWARE\Veeam\Veeam Backup and Replication" `
-Name FileCacheLimitPercent -PropertyType DWord -Value 0 -Force

veeam-backup-replication-f2/server-2022 ... ml#p549701

[obengert]

OK, thanks.
We will set those, too.

[obengert]

For us, it looks like the update (KB5062660) also with the registry setting did not fix the issue.
In fact, the situation was realy bad and we had a lot of BSODs last week.

So we are currently migrating about 500TB (750TB with fast clone) to a temporary repository
and re-install the Windows Server 2025 repository with Windows Server 2022 ...

[Didi7]

Awfull onbengert!

[jokoenen]

@onbengert: Was it real bluescreens or just a freezes?
LG
Jo