Using FT in a stretched cluster environment

I had a discussion around using FT in a stretched cluster (vSphere Metro Storage Cluster) environment. The main discussion point was around the use of “Host-VM” affinity rules. Some people appear to be under the impression that a Host-VM affinity rule can be created to ensure the primary and the secondary FT are divided between sites.

As I heard multiple people mentioning that this was possible I decided to test it. Unfortunately it is not possible. As soon as you enable FT on a VM and that secondary is started you will not see that secondary in the DRS Rules UI? Yes you can see the secondary if you look on a host level, but not in the DRS Rules workflow, this means it is not possible to ensure the secondary VM is bound to the second site.

I wanted to point you guys to a white paper that I have worked on for the last months. This white paper was written in collaboration with Lee Dilworth, Ken Werneburg, Frank Denneman and Stuart Hardman. Thanks guys for taking time out of your busy schedule to work with me on this project! This white paper is about vSphere Metro Storage Cluster solutions (aka stretched clusters) and specifically looks at things from a VMware perspective. Enjoy!

VMware vSphere Metro Storage Cluster (VMware vMSC) is a new configuration within the VMware Hardware Compatibility List. This type of configuration is commonly referred to as a stretched storage cluster or metro storage cluster. It is implemented in environments where disaster/downtime avoidance is a key requirement. This case study was developed to provide additional insight and information regarding operation of a VMware vMSC infrastructure in conjunction with VMware vSphere. This paper will explain how vSphere handles specific failure scenarios and will discuss various design considerations and operational procedures.
http://www.vmware.com/resources/techresources/10284

metro cluster