7.1 Virtual Machine Placement

Architecting a Hybrid Database Strategy with Microsoft SQL Server : Architecting a Robust Technical Platform : 7.1 Virtual Machine Placement

vSphere HA and DRS can automatically perform virtual machine placement for initial power on or when the cluster is under resource contention. To avoid a single point of failure when running AlwaysOn Availability Groups across virtual machines in a vSphere HA or DRS cluster, configure WSFC virtual machines on different physical hosts. The following practices can help to achieve this requirement:

• Create a DRS anti-affinity rule to keep virtual machines on different hosts.

• Enable strict enforcement of affinity rules.

• Set the DRS automation level for WSFC virtual machines to Partially Automatic.

If the advanced option for vSphere DRS, ForceAffinePoweron, is set to 1, strict enforcement of the anti-affinity rule is adhered to. VMware recommends using multiple server racks for the ESXi hosts and distributing the vSphere clusters across the server cabinets to minimize the impact of a single component failure.

Refer to Setup for Failover Clustering and Microsoft Cluster Service at https://pubs.vmware.com/vsphere-60/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-60-setup-mscs.pdf for detailed setup procedures.

To set up anti-affinity rules to keep virtual machines on separate hosts, follow the instructions found in Affinity or anti-affinity DRS rules are not applied during a virtual machine power-on (2003128) at http://kb.vmware.com/kb/2003128.