vSphere DRS Cluster Limits Introduced with vSphere
Recently, I wrote how certain vSphere configurations will introduce limits to consolidation ratios on HA-enabled clusters. With that information, I thought it a good idea to share another piece of information from the Configuration Maximums document for vSphere.
For a DRS-enabled cluster managed by vCenter, there is a supported maximum of 1,280 virtual machines powered on concurrently. In VI3, there was no limit other than the 2,000 VMs per vCenter server. Why the introduction of a limit? Well, that's complicated. DRS has advanced in vSphere, with two big additions. The first is the fully supported addition of Distributed Power Management. Previously in VI3, that was experimental. The other key addition is the vApp group. A vApp group is a collection of VMs that can be managed as a single object, including their resource management.
Like the HA VMs per host limit that is put into certain clusters, this DRS limitation per cluster can seriously impact design planning. VDI implementations can easily hit 1,280 VMs per DRS cluster, so then you make the decision to not make it a DRS cluster. For server consolidation, DRS is a must, yet scaling to additional clusters is something many administrators may groan about.
This isn't earth shattering, but just a call that we all should review the current configuration maximums document for vSphere.
Posted by Rick Vanover on 05/28/2009 at 12:47 PM