We are upgrading our vCenter from 3.5 to 4.1 and upgrading our hosts to ESX 4.1 and I have a couple questions. We are actually rebuilding our vCenter server from scratch, installing 2008 server x64 and installing SQL 2008 standard on the server with vCenter 4.1. Once this is done, we are reattaching our hosts to vCenter, and plan to vMotion our guests to free up one of our hosts. We will then use update manager to update ESX to 4.1 on the free host, as well as VMware Tools and hardware. We will then move guests via vMotion to free up the next host and repeat the process until all hosts are upgraded. Am I correct in understanding that all guests must go through a power-on-reset to load the new VMware Tools and hardware? Can the guests run OK for a period of time before this is done (so we can schedule the outage at a more convenient time for the users)?Thanks for any help.
Yes your guests can run ok, Hardware version 4 and legacy tools with 4.1.
When you do upgrade you can do it manually or with Update Manager, the tools first with a reboot then power-off and upgrade the hardware, this route ensures that the required drivers are there for the new hardware at next boot, if you do the Virtual Hardware first then you may not be able to boot the vM.
There is no reason to upgrade until you are fully converted. Old versions of Tools and or hardware will function just fine, you just won't have access to any of the new features available until you do. I went months before converting without issue.
Am I correct in understanding that all guests must go through a power-on-reset to load the new VMware Tools and hardware?
Correct. And 2 different step are required: first VMware Tools and then virtual hardware upgrade.
Also note that new VMware Tools can run well also if the VM is on and old host.
So you can start with this step and when the latest 3.x host is removed you can start with virtual hardware.
One for VMware Tools.
And two for virtual hardware (the second reboot is needed because of hardware changes).