I have a 3 host VMware cluster with ESX 3.5 and vc 2.5 the servers that ESX is running are not ESX 4 compatible. I will be purchasing new servers in the next several weeks for use with ESX 4 and vcenter server 4. Will the following upgrade strategy work.
Upgrade virtual center 2.5 to vcenter server 4.
Vmotion guests off of one host in the cluster to the other 2 hosts.
Remove the first ESX3.5 host from the cluster.
Add the first ESX 4 host to the cluster.
Repeat the above process of vmotion and adding hosts until the 3 ESX3.5 hosts have all been replaced.
Thank you.
Download the migration checklist. http://www.vmware.com/files/pdf/vsphere-migration-prerequisites-checklist.pdf
Webcast http://www.vmware.com/a/webcasts/details/248
As stated you will want to look at the checklist but basically your idea is right
I would use separate clusters rather than putting the new hosts in the existing cluster.
After the move you will of course have to worry about updating vmware tools, Virtual hardware and VMFS (If you use it).
Also watch processor compatibility for vmotion, otherwise you will have to power off the virtuals to move them
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