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:
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Since deploying the Nexus 1000v, it set our slot sizes in the cluster to 1.5GHz and 2GB of RAM. Not wanting to waste slots in our cluster by guests that may not reach that size (or partially fill slots), I wanted to carve out the cluster into slots of a lesser size, similar to using smaller block sizes on a drive to maximize space.
Using percentage reservations with vSphere, you can get by the slot sizes, but what if you’re starting a small cluster and growing it as resources are needed? How could I carve 25% out of a 2-node cluster? Sure, you can do it, but if you’re operating at the full 75% (with 25% reserved for failover) and lose a host, you actually don’t have enough resources and are over-committed by 25%.
Setting the following settings will help reduce your slot size, but may also have a negative impact by not having enough reservations if you end up in a failover state.
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