MSCS Question

[woodycollins]

Here in our environment we have a set of VM's setup with microsoft clustering and configured in a CAB fashion.  These boxes are configured per the documentation vmware has released on how to setup a MCSC cluster between multiple hosts using RDM in physical mode.  Everything is working in that aspect.

But I was just curious. Does anyone know what would happen if you were to use a shared controller configuration (similar to a CIB configuration) only across multiply physical hosts?

[NuggetGTR]

Little unsure what your asking,

do you mean what would happen if the MSCS that has been setup for CAB was put on a single host? so was setup for CAB but was sitting as CIB?

If that the case then I can tell you from personal experiance it will "work" but its very very flakey and issues will arrise mainly with failing over of resources. While we had SAN issues with locking disks moving them to the single host so that is was the same HBA worked but wasnt great.

Cheers

[woodycollins]

Not exactly what I was asking.  Sorry I didn't give much detail.  I was wondering if you have 2 ESX host's with a shared storage solution so the VMFS volumes are reachable by both hosts.  And you built 2 seperate VM's (one being on each host) and configured the VM's to use a shared vmdk (located on the shared vmfs volume between the two hosts) with a scsi controller of the VM configured for shared bus.  What would happen?

I understand that each hosts creates locks for VM files when the host has the VM powered on but was unsure the interaction of how a vmdk and the locking mechanisms of the vmfs filing system works when a VM is configured to have a shared scsi controller.

[woodycollins]

Alright for giggles I brought up a test cluster with the configuration I described and it works fine.  So I wonder why MSCS isnt supported in a multiple host configuration were the shared storage is simply shared VMDK's across VMFS volumes that all the hosts have access to?