1 Reply Latest reply on Mar 25, 2019 2:39 AM by rleon_vm

    Intelligence in a VSAN Stretched Cluster to vMotion VMs to the other site under certain conditions

    rleon_vm Novice

      Hi all,

       

      Suppose in a VSAN Stretched Cluster:

      • A VMDK's storage profile is PFTT=1, SFTT=1.
      • Using VM-to-Host affinity "should" rules to bind the VM to the Preferred-Site.

       

      Just want to see if it is possible for a VSAN Stretched Cluster to automatically vMotion a VM to the other site when for example:

      • SFTT in the Preferred-Site becomes non-compliant. E.g., 2 out of 3 components become unavailable (less than 50% votes).
      • Or, all 3 components in the Preferred-Site become unavailable (0% votes).
      • ...But at least one ESXi host in the Preferred-Site is still running

       

      Normally, with the affinity rule in effect, HA would restart the VM on the surviving ESXi in the Preferred-Site, even if it means the storage traffic has to traverse over the Inter-Site-Link to the Secondary-Site (Where SFTT is still compliant).

      Is there a way to make it so that in such scenarios, DRS would just ignore the affinity "should" rule for the VM, and just vMotion the VM across to the other site where the VM's storage traffic could happen locally?

       

      Thanks!

        • 1. Re: Intelligence in a VSAN Stretched Cluster to vMotion VMs to the other site under certain conditions
          rleon_vm Novice

          Sorry for the bump. I will rephrase my question to make it clearer.

           

          We have:

          Preferred-Site: 2 of 3 hosts failed

          Secondary-Site: 3 of 3 hosts still healthy

           

          What happens at the VMDK level:

          VMs can only access their VMDKs using the Secondary-Sites component copies.

           

          What happens at the VM runtime level:

          VMs can still run on the Preferred-Site's remaining host, but access to their VMDKs will have to go through the ISL to the Secondary-Site.

           

          What I'm asking:

          In the above scenario, it would be better for HA (or DRS) to just restart (or vMotion) all VMs to the Secondary-Site, ignoring the affinity rules. Anyway to do this?