sigmaitservices
Contributor
Contributor

Multiple failover hosts in a vSphere 5.1 stretched cluster

Hi,

I have a question how the below note should be interpreted, we are running a stretched vpshere 5.1 cluster with affinity rules keeping the VMs on hosts where their data resides.

We would like to have 2 failover hosts in the cluster, preferably one per site if a host on that site is lost but I´m aware that this might not be possible.

But does the below note mean that VM-VM affinity rules can´t be used at all in the cluster in normal operations if I enable (multiple) failover hosts?
Or does it only apply in a HA-failover scenario?

Note

If you use the Specify Failover Hosts admission control policy and designate multiple failover hosts, DRS does not load balance failover hosts and VM-VM affinity rules are not supported.

pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vsphere.avail.doc_50%2FGUID-C4F5F9EE-4235-4151-BEBE-FCB2A752407B.html

Thanks...

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depping
Leadership
Leadership

sigmaitservices wrote:

Note

If you use the Specify Failover Hosts admission control policy and designate multiple failover hosts, DRS does not load balance failover hosts and VM-VM affinity rules are not supported.

pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vsphere.avail.doc_50%2FGUID-C4F5F9EE-4235-4151-BEBE-FCB2A752407B.html

Thanks...

I've never seen this part to be honest. I am assuming you are not using VM-VM affinity rules but rather VM-Host affinity rules? I will validate the below statement for you, but my interpretation is:

When using Specify Failover Host the hosts designated will never be used by DRS for Load Balancing and will not be considered by VM-VM affinity rules.

So from an HA perspective this should not be a problem as far as I can tell.

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