Forum Discussion
Nested-V Dedup corruption 26100.1742 and Insider 26296.5001 (and Server 2022) is still there.
MicrosoftHello Joachim_Otahal
I have a few clarification questions.
While configuring dedup on 😧 of L1 guest, did you use VDI profile?
And did you set "deduplicate file older than" to 0 days?
On L1 Hyper-V, when you import the L2 VMs, what import type option did you use?
We have not been able to repro the issue internally with the VDI profile on either WS2022 or WS2025 as the L1 OS.
Given that it is reliably reproducible for you, could you please do the following?
a) enable full dump on both the L2 guest VMs by running:
reg add "hklm\SYSTEM\CurrentControlSet\Control\CrashControl" /v CrashDumpEnabled /t reg_dword /d 1 /f
b) Do the repro. If you can, save the output of chkdsk C: /f or chkdsk C: /scan run on the L2 guest VMs
c) Share the system.evtx, Application.evtx and Microsoft-Windows-Ntfs%4Operational.evtx from the L2 guest VMs. They are under C:\windows\system32\winevt\Logs folder.
d) Run the command: fsutil repair enumerate C: on both the L2 guest VMs and share the output.
e) Share the system.evtx, Application.evtx and Microsoft-Windows-Ntfs%4Operational.evtx from the L1 guest VM
f) If either of the L2 VMs bluescreen, please share the dump.
Greatly appreciate your input in figuring out this issue.
Thanks
Thank you for your reply!
Which profile: Does not matter, happens with all three (as described in previous. postings..).
"Deduplicacte older than 0 days" is only needed if the L2 VMs are fresh set up, before starting any Windows Update. If you import existing VMs without starting them, which have not been touched for > 3 days, you don't need "0 days".
How to import the L2 VMs: Attach the VHDX, open Hyper-V GUI, import "register directly". Exactly as in the video.
As for sharing the crashed: I will follow your additional preparation instructions, and then provide you with the complete VM package "right before dedup", "right before the final repo step", and "after L2 VMs died", which includes the L1 OS and the (crashed) L2 VMs. Host will be Win11 24h2, Ryzen 5950x, ECC RAM, which is important since the L2 VMs does not work on Intel hosts in my tests unless you deactivate and reactivate Hyper-V in the L1 guest.
Do you have a special request regarding what OS the 1st or 2nd level guests have to be? Else I'll use "Server 2025 with updates" for L1 guest, and "Server 2012 R2 German and English" for L2 since the latter are already there.
regards,
Joachim Otahal
- MSSWRahmanThank you for the clarifications, Joachim.
Please use VDI profile because that is the recommended one in this scenario. For the L1 guest please use server 2025, because that is where dedup is being enabled. For the L2 guest, feel free to use server 2012. I guess L2 could be any OS; I was using server 2022.
Also, my attempts have been on Intel hosts so far. I will try your tip of deactivating and reactivating Hyper-V in the L1 guest (before starting the dedup job i guess).- MSSWRahmanJust one more thing. You may be knowing this already, but when you enable full dump on the L2 guests, please check that pagefile is enabled on C: and is big enough to accommodate the RAM size on those VMs.
After you get the repro, do share the logs mentioned in points c), d), e) and f) of my initial post.
Thanks
