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  • 1.  Can you disable vSphere HA temporarily in a VSAN cluster?

    Posted Mar 14, 2017 05:53 PM

    My VSAN cluster has been reporting a configuration issue, in that a HA event occurred and 1 VM is still waiting for a retry.  I had no HA event.  I have no idea of which VM it thinks is waiting for a a retry.  This started after I cycled through the cluster, doing patches and reboots of the ESX hosts.  (9 node cluster).

    I had a SR open with support.. after a lot of digging.. they suggest I turn off HA and turn it back on again.  Back in the pre-VSAN days, that would be an easy thing to try.

    Can I do this with a VSAN cluster?

    I seem to remember trying it once in pre-production days, and it said something like "Disable VSAN and then disable HA".. which obviously I can't do now.

    I asked them to check 3 times this answer.. support assures me I can do this in a VSAN cluster with no loss of data availability.

    Any thoughts on this?  I really need to build up a test bed and try it.

    Thank you.



  • 2.  RE: Can you disable vSphere HA temporarily in a VSAN cluster?

    Broadcom Employee
    Posted Mar 14, 2017 08:44 PM

    HA is supported with VSAN but it is not a requirement (though in most cases you will probably use both) so there should be no reason why you can't disable and reenable HA - it will not stop VSAN from functioning.

    With regards to your message the only thing I can think of is that HA must be disabled prior to enabling VSAN (though it can obviously be enabled afterwards). That specific sequencing is the only thing I'm aware of though not relevant to what you are looking to do here.



  • 3.  RE: Can you disable vSphere HA temporarily in a VSAN cluster?

    Posted Mar 14, 2017 08:58 PM

    There should be no negative impact from temporarily disabling and then re-enabling HA on a vSAN cluster.

    HA is working at the vCenter level, even that cluster you see in the client is only really at the vCenter level, the actual vSAN cluster is formed and maintained between the hosts themselves communicating directly and via Multicast. Even if the vCenter got destroyed the vSAN cluster would still be fine (from a data perspective that is - VMs would obviously not get auto-restarted without vCenter and HA enabled)

    Perhaps you are mis-remembering the alert previously when trying to enable vSAN:

    "You must disable vSphere HA before you enable Virtual SAN on the cluster. Then you can reenable vSphere HA."

    https://pubs.vmware.com/vsphere-60/index.jsp?topic=%2Fcom.vmware.vsphere.virtualsan.doc%2FGUID-D68890D8-841A-4BD1-ACA1-DA3D25B6A37A.html



  • 4.  RE: Can you disable vSphere HA temporarily in a VSAN cluster?

    Posted Mar 15, 2017 02:00 PM

    Just to be clear: HA also works on a host level. Even without vCenter Server itself going down you would still be able to restart VMs as long as HA is enabled. And yes, you can disable and enable HA while running vSAN. No issue whatsoever.