I upgraded one of my lab hosts to ESXi 4.1 yesterday and was plagued with this error:
A lot of people are getting this error without a lot of direction. As it turns out, this is because I upgraded one of my hosts to 4.1 without upgrading vCenter to 4.1. Silly me! Who would have thought that vSphere vCenter couldn’t manage a vSphere host because it’s rev is 0.1 higher?
ESXi 4.0 Update 1 brought with it one major update (as I pointed out here). Now that 4.1 was released on July 13th, I wanted to take a look and see if anything else major has been changed.
Biggest change was they lifted the 160 VMs per host in an 8-node HA cluster. Now it’s the maximum of 320 VMs per host, and a maximum of 32 nodes per HA cluster. Problem is, they imposed a maximum of 3000 VMs per cluster (standard, HA, or DRS, they no longer differentiate them), so you’d just have to find your sweet spot to maximize how you want your cluster set up. Not that 3000 VMs per cluster is a problem, but if you ran 320 VMs on 75% of a 32-node cluster (leaving 25% for failover), that’s 7680. That’s a difference of 4680 VMs. At any rate, I’m glad they lifted the 40 VMs per host in a 9+ configuration.
The Configuration Maximums for 4.1 can be found here.
Here are some of the key features that have changed: