SimpliVity Primary and Secondary copies

[CadenLange]

Hi all

I have an 8 node SimpliVity cluster (running 4.1.1U1 all on a single site and without Availability Zones configured.

There aren't that many VM's running on this cluster and plenty of compute resources available - such that I can easily place 2 or 3 hosts into Maintenance mode without running lower on compute resource.

My question is the what happens to a VM that has a Primary on host 1 and a secondary on host 2 and these are the two hosts I want to put into maintenance mode?

I guess putting Host 1 into maintenance mode will migrate all the VMs off Host 1 and onto the hosts containing the secondary copies (which are then promoted to Primary?), after which the OVC can be shutdown.

But if I then proceed to place Host 2 into maintenance mode what happens to the VMs whose replica copy was on Host 1? Will the VMs move to a different available host but my attempts to subsequently shutdown the OVC then stall at the 'waiting for Storage HA' stage whilst it's rebuilding a new secondary on another host?

Thanks

[Mahesh202 · Accepted solution]

Hi CadenLange

Hope you are doing well.!!

The system will not allow doing that until the first copy come back and rebuilding will not start because the node is still in the cluster with a faulty state. Instead, remove nodes one by one from the federation and wait until the rebuilding of the secondary copy is done at the cluster level. I mean remove the first node from the federation and wait until rebuilding is done. Then check to all resources if you have still enough CPU, memory, and storage space in the cluster in order to remove another node. If the everything is fine then you can remove another node from the federation

Hope this helps.!!

Regards
Mahesh

[CadenLange]

Hi Mahesh

Many thanks - understood. Probably won't be remvoing nodes from the federation to allow for hosts to undergo maintenance at the same time. Seems more sensible to only ever work on a single host at a time irrespective to how many hosts in the cluster.

So it doesn't matter how much available compute resource you have within the cluster it's only ever possible to place one host at a time into Maintence Mode..... and even then, you need to hope a second host doesn't fail during the maintenance period - else several VM's are likely to go offline.

Kind regards

[Mahesh202]

Hi CadenLange

Yes if they go to maintenance mode with more than one node at a time some of the VM will be inaccessible according to hive p&s copy placement.

Hope this helps.!!

Regards
Mahesh.