Inaccessible Boot Device after trying to patch Hypervisors

Question

I recently tried patching our 3 node Hyper V cluster for the first time using Cluster-Aware Updating (CAU). After installing the patches on the first node (01) it rebooted and now will not boot back into Windows (patches were not installed on the other nodes due to these patches failing to complete). The server now gets a blue screen with an error saying 'Inaccessible Boot Device'. All 3 nodes are physical Gen 10 servers running Windows Server 2019. We are using storage spaces direct with a 3 way mirror configured on the disks.

It is important to that this node (01) has a VM that has a SAS tape library physically passed through to it. None of the other nodes have this configuration.

Troubleshooting steps I've tried so far:

• I have physically removed the SAS tape library to make sure this wasn't causing the boot issue.
• I have checked the boot order to make sure the server is trying to boot to the correct disk.
• I have tried running a repair of the server using the ISO.
• Rebuilt the BDC.
• Uninstalled the patches using cmd prompt.
• Updated the Service Pack for ProLiant (SPP) to the latest version.

But still we are getting the 'Inaccessible Boot Device' screen. I believe this may be something to do with the SAS tape library pass through rather than the updates that were installed. Has anyone come across this before with this configuration?

I have been advised that the only way to get this resolved is to rebuild the node. This is looking like our last option but doesn't stop this issue from re-occurring again when we next patch the cluster.

Can anyone please help?

Thanks,
Tom.

Answer 1

Hi Tom,
Indeed, System restore, backup image or rebuild are often the quickest way to recovery.
According to your description, you have tried some methods to repair just like rebuild BCD and a repair of the server using the ISO.
Another you could try to use diskpart command to check if C drive is active.
https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows-boot-failure
As you said, the issue sounds like after installing updates a change in the hardware configuration of devices that are boot critical. whether a specific driver can't be set to load automatically at system startup.
I consider that you may open a ticket with Microsoft and SAS tape. It seems to have to do with SAS controllers.
Hope this helps and please help to accept as Answer if the response is useful.
Best Regards,
Carl