Hyper-V R2 Cluster Scalability

As of June 2010, the Failover Cluster team upped the support limit to 384 virtual machines per node to match the Hyper-V maximum of up to 384 virtual machines per server. In addition, the overall number of running VMs per cluster has been bumped to 1000 VMs in a cluster. Thus, we now support up to 1000 VMs in a cluster, whether that’s a:

· 5 node cluster (4 active nodes each running 250 VMs + 1 failover node)

· 11 node cluster (10 active nodes each running 100 + 1 failover node)

 

Here’s a quick table:

 

Number of Nodes in Cluster	Max Number of VMs per Node	Max # VMs in Cluster
2 Nodes (1 active + 1 failover)	384	384
3 Nodes (2 active + 1 failover)	384	768
4 Nodes (3 active + 1 failover)	333	1000
5 Nodes (4 active + 1 failover)	250	1000
6 Nodes (5 active + 1 failover)	200	1000
7 Nodes (6 active + 1 failover)	166	1000
8 Nodes (7 active + 1 failover)	142	1000
9 Nodes (8 active + 1 failover)	125	1000
10 Nodes (9 active + 1 failover)	111	1000
11 Nodes (10 active + 1 failover)	100	1000
12 Nodes (11 active + 1 failover)	90	1000
13 Nodes (12 active + 1 failover)	83	1000
14 Nodes (13 active + 1 failover)	76	1000
15 Nodes (14 active + 1 failover)	71	1000
16 Nodes (15 active + 1 failover)	66	1000

 

Keep in mind that increasing the number of VMs of per node only magnifies the need to perform proper capacity planning that takes into consideration the capabilities of the hardware and storage to host VMs and the total resources that the individual VMs require while still having enough reserve capacity to host VMs in the event of a node failure to prevent over commit.

 

This is a great example of the Cluster team responding to customer feedback and requests for greater VM density. THANKS!

 

Finally, this change is publicly documented here on TechNet: https://technet.microsoft.com/en-us/library/ee405267(WS.10).aspx