15. dubna 2012 10:35I'm in a need of being able to access a large data file from 2 VMs. I will run only one at a time. The host machine has 2 physical drives. Would it make sense in this case to use the second drive as a pass-through disk or fixed size? If I attache it to one of the VM's will I be able to attach it to the other one when the first is powered down or will there be complications?
15. dubna 2012 14:34
If you use only one of the two VMs at a time, then yes, you may use the same VHD file for both VMs.
Actually, if you try to power ON the second VM (when the first VM has the VHD file mapped), the second VM will not power ON and will throw an error.
16. dubna 2012 15:12Moderátor
This used to be salled the 'shared scsi bus' in virtual server.
It is no longer possible, mainly becuase most operating systems have moved away from support due to the advancement of SAN - you rarely see it as a hardware option any longer.
One way to handle this is using iSCSI to present the contenct of the volume to the VMs. (this is what you would need to do to cluster).
Another way of handling this is to use a differencing disk between the VHD and the VMs. This allows READ of the root VHD but not write. That is the hitch.
If you have Windows in the VM, the only way this is even possible is with Clustering enabled - and then only supported if using CSV. With 2008 R2 that only applies to the Hyper-V Role in the VM. In Win8 it extends to the File Server Role.
Learn. Apply. Repeat.
Disclaimer: Attempting change is of your own free will.
17. dubna 2012 16:49Brian I'm talking about a test environment where currently I run 2 VMs under VPC and created a vhd share so I can attach it where needed. Both the VMs are stored on the same disk (I know...) but it's the data that needs to be accessible via one of them to and external PC. I found that when I move each of the VMs on separate disks and the share vhd one it's own drive it works better but far from perfect. I'm getting pretty slow transfer rates. This is why I think of moving it all to Hyper-V 2008 R2 machine and move the data of the vhd onto a disk set to run in passthrough.