Server 2025 - high CPU and RAM

[Gostev]

Maybe consider switching to VSA then. It uses proven XFS-based storage stack with zero issues in Support in the past 5 years. XFS is simply far more mature, and with Veeam controlling the entire appliance there will never be surprises from 3rd party software either.

[jackal2001]

Installed the Dec 2025 CU but also have the following REG Keys still set.
RefsEnableLargeWorkingSetTrim -PropertyType DWord -Value 1
RefsNumberOfChunksToTrim -PropertyType DWord -Value 16

Also tried excluding MS Defender from scanning my repo volumes, disabled disk defrag that is built into windows as a scheduled task, etc. I don't even know if those reg values apply without even applying the "patch" MS provided to a select few a couple months ago.

Update, my Repo server has been up for 25 days now running since installing the patch. I have a 50TB and 30TB REFS volume using 32GB of RAM on the VM, which at this point seems to not go higher than 40% utilization.

[cbc-tgschultz]

Also updating: Things went smoothly since last time (reg key changes, official server patch via WU) except for Friday morning, when the system was stuck at 100% CPU and unusable for long enough that I just bounced it to get going again.

At this point we're already building a new set of backup storage and replication targets anyway, so we've decided to to just leverage them as Linux repositories with XFS, which seems to be not only rock solid but also much faster at block cloning anyway. Looking forward to the day that Veeam gets ZFS reflink support (outside of the TrueNAS enterprise support for it via SMB) so I can remove an abstraction layer.