We have three Virtual Host machines, 1 running VMWare ESXi and two running Hyper-v. We've been fairly impressed by ESXi (aside from a few teething issues...) and we're considering converting our existing Hyper-v hosts and VMs to ESXi.
We were able to get our ESXi host using our iSCSI SAN quite easily, and i know it has some clustering abilities at the VMFS level but i'm finding it difficult to get any information on exactly what those abilities are. What we want to do as follows:
For the sake of this discussion i have ESXi Servers 1,2&3. I have an iSCSI server with LUNA configured through iSCSI Target A.
Is it possible to have many servers 1,2&3 all connected to LUNA through iSCSI Target A. The three hosts would have to be running different VMs obviously but are they going to fall over each other (as in stop working not fail-over) if the vmdks are on the same file system accessed simultaneously? Is there some step i would need to take to make Hosts 1,2&3 aware of each other so that they don't or does it just happen with the magic of vmfs?
My disks would be preallocated but what about snapshots etc which are not, would that maybe cause issues? Each VM Host would be running up to a dozen or so VMs on it and i'd ideally like to use only the one lun for all 36 guests on the three hosts.
We basically just want to do poor man's high availabilty, similar to this little blog post: http://communities.vmware.com/message/1273289#1273289 .
Am i dreaming or is it possible with ESXi?
VMFS allows for concurrent connections to a single LUN by multiple ESXi hosts, this is not to say that you can allow multiple VM instances (on the same or different hosts) to operate from the same virtual disk file, so windows file system behavior is not in question. The 'poor man's high availabilty' described here would basically be two hosts having access to a virtual disk with an OS on it, but only one of them using it at any given time.