vCenter HA and Datastore Cluster Incompatibilities...

[mckenp]

All,

Change window came and I cheerfully set about reconfiguring HA vCenter across one of the DCs. At the point where I wanted to clone the primary vCenter, the HA wizard invited me to choose destination datastores for the passive and witness nodes.

It appears that any datastore cluster CANNOT be chosen as storage locations for vCenter HA. I have not found any VMware docos that mention this limitation, just a post on a blog in passing that it was a non-starter.

I assume that (by default) if one was to provision the disks for the passive and witness nodes, storage DRS would take over and offer no guarantees that the primary, passive and witness disks would remain on seperate LUNs within the datastore cluster - so this undocumented limitation makes sense.

However, if I was to set up (anti)affinity rules to keep the disks apart within the cluster, surely this would be a compliant situation?

As we have tiered storage - all clustered - the only workaround I can think of is to drop one of the LUNs out of the datastore cluster, provision vCenter HA all on the same LUN, drop the LUN back into the datastore cluster then configure affinity rules. The same blog post mentioned that one would need to create three dedicated datastores just for vCenter HA, which doesn't conform with the architectural vision of the storage layout on our platform.

Any ideas?

Cheers,

Pete

[parmarr]

As I understand, you are deploying vCenter HA in Advanced mode.  Choosing the datastore depends on the cluster you have chosen as compute resource. Any data store can be selected which is available to that cluster.

I don't think there is any limitation as such on datastore selection.

As you are in advanced mode, you need to setup the anti-affinity rules. in Basic mode, this is all taken care by the system.

It is ideal to select a different cluster, different datastore and hosts to avoid any single point of failure. But there is no hard rule to force these settings.