ESX 3.5 & 4

[Rohail2004]

Can I have a cluster which has 2 ESX 3.5 hosts, and 1 ESX 4 host? I know as long as I dont upgrade the vm hardware they should work? correct? do I need to upgrad the VMware tools or wait until all three hosts are up to ESX 4.0? What precautions should I take before moving VM's from ESX 3.5 to ESX 4 host within a cluster?

[RParker]

Yes that will work, and yes both hosts are fine in the same cluster.

But if you have ESX 4.0 why can't you upgrade the other to ESX 4.0? Apparently you have 2, migrate the VM's, convert one to ESX 4.0, then do the other.. no?

[Rohail2004]

That is my plan to convert other 2 hosts to ESX 4.0, but I want to upgrade one at a time to make sure it does not cause any major problem, since I will be doing in production systems.

[JimmyOOOOO]

What precautions should I take before moving VM's from ESX 3.5 to ESX 4 host within a cluster?

Ensure that you have a solid full backup and go for it, the VMs won't care whether they're running on 3.5 or 4. As an added benefit, you will be able to use Storage vMotion to Thin Provision the disks and possibly free up some space in your storage environment.

If you're extra nervous about moving the VMs, you could use the Migrate functionality and leave a copy of the VM on the 3.5 host (powered off obviously) until you have verified that is up and running to your satisfation on the new host.