With the release of vSphere 4.1 there have been some great enhancements that have been added with this release. In one of my earlier post I took a look at the vSphere 4.1 release of ESXi. This post I am going to take a look at vSphere 4.1 availability options and enhancements. So what has changed with this release? A maximum of 320 virtual machines per host has been firmly set. In vSphere 4.0 there were different VM/Host limitations for DRS as well as different rules for VMware HA. VMware has also raised the number of virtual machines that can be run in a single cluster from 1280 in 4.0 to 3000 in the vSphere 4.1 release. How do these improvements affect your upgrade planning?