Mar 21 2021 05:36 AM - edited Mar 21 2021 05:37 AM
Dear Server / Storage Team,
I am running a lab with Windows Server 2022 LTSC preview to get familiar with the new or changed features but also to help you hunting issues.
For a very long time now I faced issues with "semaphore timeouts" reported by the Macrium backup solution and Ned Pyle and Vlad helped me to narrow down that the issue is not a SMB issue but infact a problem with the storage subsystem.
Here Storage Spaces consisting of two WD Red Plus 6 TB. mirrored, ReFS 3.6.
In previous releases of Windows Server the issue also affected the scenario when clients tried to backup to a SMB share causing the same issue. This improved over releases
Now only one issue remains. Here is the Feedback hub item.
Scenario:
Hyper-V Host Hosting various VMs
one VM data disk (VHDX) is located on a Storage Spaces Pooling using Dedup (dedup will run outside backup times)
When the backup application runs it will write the data from this vhdx via Block Level (tested with or without CBT) to a file share (driveletter A)
The timeout will occour reproducibly and so preventing a backup.
If I try the same and do not use the SMB Share located on a volume on the Storage Spaces Pool the backup is fine.
Source: VM > Data disk (driveletter N) located on Storage Pool 1 volume (driveletter H)
Target: SMB Share (driveletter A) located on Storage Pool 1
Error: semaphore timeout
more details in the feedback hub from our investigation
unaffected builds
Windows Server 2019 LTSC 1809 17763.x
Windows Server vNext LTSC b20215
affected builds:
all other Windows Server vNext / 2022 LTSC
the issue happen when the backup data amount is large (20-40 GB will work fine)
Mar 25 2021 01:44 PM
Mar 26 2021 08:01 AM
@RahulTK since this is a quite complex topic would it be possible to have a teams meeting?
Apr 01 2021 08:16 AM
@RahulTK in the release Windows Server 2022 LTSC 20313 the issue disappeared but I would not mark it as solved. There have been a lot of changes and Unfortunately I didn't test enough after each change, sorry.
1. upgraded the VM (backup source) from 20H2 to 21H1
2. upgraded Server Hyper-V Host (and SMB Share holder to 20313)
3. upgraded from Macrium Reflect 7.3.x to 8.0 beta, this one has not the same feature set (CBT and backup file encryption are no longer in place)
4. I have disabled the scheduled jobs for automatic background optimization for Dedup and only run the base scheduled jobs. Reason for this was a problem i have seen in b20292
in https://techcommunity.microsoft.com/t5/windows-server-insiders/b20292-cpu-spikes-since-b20292-due-de...
next steps:
I can provide you the logs via Onedrive
When MR 8.0 final is out I will try to enable the CBT and later encryption to see if one of these are causing the issue.
When this scenario has passed I will enable the background optimization again.
Apr 08 2021 01:29 AM
May 23 2021 03:30 PM
Solution@RahulTK This week I have upgraded to Macrium Reflect 8 which enabled all the previous features like CBT and encryption and it still works like a charm.
This means the issues with the setup
2 HDDs with Storage Spaces Mirror where source vhdx and backup target (filebased) are stored on a ReFS volume with enabled Dedup gives no headaches.
From my trackings I'd say it has been fixed in b20313
May 23 2021 03:30 PM
Solution@RahulTK This week I have upgraded to Macrium Reflect 8 which enabled all the previous features like CBT and encryption and it still works like a charm.
This means the issues with the setup
2 HDDs with Storage Spaces Mirror where source vhdx and backup target (filebased) are stored on a ReFS volume with enabled Dedup gives no headaches.
From my trackings I'd say it has been fixed in b20313