I am in the process of evaluating vendors for upgrading our existing VMware environment. In a conversation with a provider, he told me that vMotion was not possible without a separate SAN appliance or vSAN (the latter requiring 6+ hosts and expensive licensing).
Under the impression that our 3-host cluster already had vMotion licensing and capability, I tried to "vMotion" a running Windows VM using the vSphere client. I was able to "migrate" both the VM and its disk to a new host and datastore respectively, but nowhere did I see the term "vMotion" in the Recent Tasks log at the bottom of the UI. What I did see there was "Migrating Virtual Machine - Active State" and I was able to maintain an RDC connection and interact with the VM all through the migration process.
My question: Am I misunderstanding the term vMotion? Is it different than migration in an "active state"?
Also, assuming vMotion is an unattended convenience and seeing as we already have an image-level backup solution for our VMs and my company is okay with manually restoring those VMs from a backup (as opposed to the convenience of an "instant," unattended, back-end restoration), is vMotion worth the investment in a dedicated SAN server if we're already capable of "live migration" on demand?
And don't worry about selling me on all the benefits of a SAN. Believe me, I'm already with you on that. The people over here who sign the checks just have different priorities is all.
TWIMC: We're in a 3-host cluster, ESXi 6.0 on all. Enterprise Plus licensing.
vMotion is VMware's branding for being able to migrate powered-on / running Virtual Machines from one ESX/ESXi host to another. vSphere UI does not refer to the actual operation in the UI as vMotion except for a number of places where the branding matters i.e. when configuring a feature called Enhanced vMotion Compatibility (EVC) or when enabling vMotion traffic through specific VMkernel virtual network adapter.
On the point about vSAN / physical SAN being mandatory - you already confirmed that you can migrate the VMDKs of a live VM so it's not a complete necessity. The official docs have a section about the limitations of simultaneous comput + storage migration: https://docs.vmware.com/en/VMware-vSphere/6.0/com.vmware.vsphere.vcenterhost.doc/GUID-9F1D4A3B-3392-46A3-8720-73CBFA000A3C.html.
I'd bet that migration should be faster if only the memory image of a powered-on VM is migrated - this is especially true in automated DRS setups where VMs are migrated automatically based on a pre-configured policy. Users on reddit seem to have tested this - https://www.reddit.com/r/vmware/comments/matict/vmware_drs_cluster_without_shared_storage_das/gru579m/?utm_source=reddit&utm_medium=web2x&context=3.
Note that I am a VMware employee (albeit not in sales), and you'd probably want a different, unbiased opinion about the product's merits ;)