We currently have 3 VMware hosts, all running ESXi 4.1. They are all HP DL380 G7's, two of them having dual Xeon E5620 cpus with 96GB RAM, and the third having dual Xeon E5645 cpus and 64GB RAN.
The two hosts with E5620's are already being managed by vCenter, and are in a cluster with VMs on central SAN storage, while the third is a single managed host with only local storage. I would like to free up the third host for use in another cluster elsewhere, by moving all the VMs to the existing cluster.
My preference, would be to simply migrate the VMs from the standalone host to the vCenter cluster. I am not sure if this is possible, firstly due to no integration with vCenter, no access to the SAN and also having different models of processor. I can't see any way to import an existing VM, so it's not like we can even manually copy all the VMDKs and config files, then import the VM.
I guess a second possible option, would be to add the standalone host to vCenter, add a Fibre HBA card for SAN access, vmotion the VM to the existing cluster, and then remove the host from vCenter. I suspect processor difference may still be a limitation here, even though they are of the same family?
Appreciate any advice on the best way to free up this host without manually rebuilding all VMs from scratch.
Best Answer
AFAIK, The CPU difference won't stop you from adding the host to your vCenter server. I have a client that has three vSphere 4.1 hosts in a vCenter server cluster all with different CPU's. You could migrate the powered off virtual machines to a new host without connecting this host to the storage array if you have a local datastore on the other hosts that's large enough for the virtual machines (either one at a time or several). Once migrated to a local datastore you can then move them to the storage array.
EDIT
Edited my answer to remove the HA reference, thanks to the assist and clarification from Eric C. Singer