Change SCSI bus sharing from "virtual" to "none"

[Johan77]

Hi,

I have one VM with MSCS installed. 

Single VM , but for some reason the scsi bus sharing is set to" virtual".

Since this isnt a real mscs cluster my goal is to have the scsi bus sharing set to "none" so I'm able to do vMotion, Snapshot etc.

Ive tried to power off the VM and then change the scsi bus sharing to "none", but when i started my VM all the disks were offline/reserved. (windows  diskmanagement).

I changed back to "virtual" scsi bus sharing and all my disks are visible again...

How do I change the SCSI Bus Sharing from "virtual" to "none"? 

Possible without destroy something?

Environment = vsphere 5.5

Problem VM = win2012

Cheers

Johan

[RyanH84]

Hi,

Are your disks Raw Device Map disks or standard VMDKs within a Datastore? Were they created /used anywhere else at any given time or was it always just a one node cluster?

Did you try and bring the disks online when you booted up with "None" set?

In MSCS, if a device is "reserved" it means that the cluster service on a host HBA owning the device has put a SCSI lock on it to protect it from being accessed by other host HBAs. You might have to work with MSCS and bring the cluster offline (or at least the cluster disk resources) before powering off the server. This should stop MSCS putting locks on the disk on startup.

At this stage, you will hopefully be able to power down, change to the controller to "none" and then power up and bring the disk online. I'd strongly advise testing this first though and not guessing your way through it, especially if it is a production environment.

It could be that changing the settings on the SCSI controller has confused MSCS somewhat. Check out this article on MS Cluster Disk reservations.

Happy to help further if needed.

Regards,

Ryan

[ScreamingSilenc]

As mentioned by Ryan you can remove the disk from the cluster then power off the VM the try changing the Bus sharing to "None" and Power On the VM, If the disk shows offline bring it online and re add to the cluster.

[Johan77]

Hi Ryan ,

Thanks for your swift reply.

The disks are standard VMDKs.

I heard that there was a plan to create a 2 node "in a box" cluster but it never happened,  always just been this single VM.

I didnt try to bring the disk online , i got so scared when the cluster disks were offline and red warnings everywhere

This server is not in production but is heavily used in our QA environment so its rather important.

This weekend i will power down the VM and then make a clone. (The VM has 24 disks , Size all together <2,5 TB)

I will then login to my cloned VM and shutdown the cluster, then power it down and try to change the scsi bus sharing to "none"

Will let you know how it went on Monday.

Cheers

Johan

[RyanH84]

Hi Johan,

I am just wondering how you got along with your disk work this weekend? Do you need any more assistance?

[Johan77]

Hi Ryan!

I cloned the server on Sunday and found some time to play around with it yesterday.

First i tried the same procedure like before, i.e just changing the SCSI bus to none, when server came up all disks were offline and i couldn't take them online (Locked by cluster)

I then shutdown the cluster and tried again, same result.  Then i rebooted the VM and then all all the disks were online

So now I'm gonna schedule a new maintenance window and solve this problem for good.

Thanks for your help!

Cheers

Johan

[RyanH84]

Hi Johan,

Thanks for the update, good to hear you made progress! Please don't forget to mark the correct answer or any useful replies!