In David Davis' article "Overview of VMware ESX / VMware Infrastructure Advanced Feature," he says that using Storage VMotion "you could move a VM guest from one ESX server's local storage to another ESX server's local storage with no downtime for the end users of that VM guest." I wasn't familiar with Storage VMotion so I started looking around VMware's website for more information about it. Based on what I've read there it seems like Storage VMotion is for moving a running VM between datastores connected to a particular host. Nothing that I read indicated to me that you could use it to move a running VM from the local storage on one ESX host to the local storage on another ESX host. Obviously I've never actually tried this so I was just wondering if someone could clarify this for me.
I did not use StorageVMotion for myself yet. but according to this what's new and what's different guide, it is used to move a VM's files from one datastore to another datastore within the same ESX server host with no downtime.
When you use ordinary VMotion between 2 ESX servers, it is, as far as I know from ESX 3.0.x, not possible to change the datastore on the target host, since it just grabs the files on the existing shared VMFS volume. I guess this still applies to ESXi/3.5, but I'm not that sure about that.
Thanks to you both for visiting the new VirtualizationAdmin.com website and for reading my article on VMware ESX Advanced features.
You both made some excellent points!
I have corrected the article to clarify & correct the example I provided on SVMotion.
An ESX Servers's local storage is called a datastore. SVMotion can more a running VM from datastore to datastore. However, there is a caveat. The source and destination must both be readable/writeable by the source of the VM. As, the local datastore on another ESX Server would not be readable/writeable by the source ESX server, then you would not be able to move a VM from the local datastore on one ESX Server to another.
However, you would be able to move a running VM from the local datastore on an ESX Server to a shared SAN datastore. Then, if you chose to, you could move that VM from the shared SAN to the local datastore on that server.