26063 deduplication data corruption is still there.

Al little update on this: I am in contact with others to reproduce this, and we came across the "write cache "setting of the drive. But even with the checkmar removed it still happens. We are trying to narrow it down, for example minimum CPU GHz speed and similar things. Sadly I cannot do such a test in the Xeon 6226R on bare metal instead of nested-V, that other machine is not mine.

Sorry for my late answer: Yes.

Base is still the AMD Ryzen 5950x with 64 GB ECC RAM (real ECC, DDR4), but as I previously tested: Happens on Intel too. Requirement: Somewhat fast storage and fast CPU, should be > 3 GHz class. The Volume where the deduptest is made on MUST be on a different physical disk than the System. If it is on the same disk as the System it won't reproduce. SSD is recommended, here a Samsung SATA 860 EVO 4 TB is fast enough, 'cause reproduding it on slower storage takes several attempts. The volume is formatted as NTFS. Drivers are default-MS supplied, not swapped or updated against OEM drivers.

The drive which I run the repo on is the fresh formatted H: Volume, but Volume F: has a lot of other VMs which all show the same result, down to the Windows NT 3.51 VM, even though it is a storage-space JBOD which uses part of the System drive. (Those VMs are backup up of course, so no real harm done).

Here as text to the screenshots (msinfo32 output is available on private contact):

Step 0 DedupTest Shot hardware overwiew.PNG

Step 1 DedupTest Volume H fresh formatted, NOT A SYSTEM DISK, in this case Samsung SATA SSD. ANY non system disk volume exposes this.PNG

Step 2 DedupTest Server2025 26100.1742.240906-0331 VMs fresh installed, PW set to empty, Updates ready on desktop, VMs exported, about to enable dedup.PNG

Step 3 DedupTest Dedup done.PNG

Step 4 DedupTest before Start updates.PNG

Step 5 DedupTest UNEXCPECTED Server 2025 core crashed even bore starting updates.PNG

Step 6 DedupTest Trying to update the two GUI installs too, crash or strange error.PNG

Step 7 DedupTest Counter-test. Reformatted volume H, imported VMs from Step 2, before starting to update.PNG

Step 8 DedupTest Counter-test. Updates started.PNG

Step 9 DedupTest Counter-test. 15 minutes later - all three updating in parallel.PNG

Step 10 DedupTest Counter-Test. Reboot after update.PNG

Step 11 DedupTest Counter-Test. Reboot after update.PNG

Step 12 DedupTest Counter-Test. Everything fine after reboot when having non dedup active.PNG

The "Ready to import Eval-Server2025 VMs, with updates prepared on Desktop" are here (still uploading, upload will be finished 1200 hours UTC): https://joumxyzptlk.de/tmp/microsoft/Deduptest-Server2025-VMs-ready-to-import-to-save-time.7z

kind regards,

Joachim Otahal

From here on: Counter-Test WITHOUT dedup, fresh formatted H: drive.