Breaking a HA-DRS cluster in two cluster

[john23]

Hi,

My client has 13 node cluster which has two generation of servers and all servers are running windows.

Server generation A (7 Servers): 24 logical CPU and 192 GB RAM

Server generation B(6 Servers): 32 logical CPU and 256 GB RAM

HA admission control policy set on cluster level :percentage resource ( 8%)

Due to different resource (cpu and mem) in servers, its unbalanced the cluster. For balancing the cluster I recommended to break the cluster in two (7 node for cluster A, and 6 node for cluster B).

Note: Target max utilization is set to 80% (without memory over commitment)

Now he asked what are the challenges he will face? Can someone give me challenge, in terms of re-configuration, please provide with details??

some of them I have plotted:

-DVS reconfiguration

-ESX level, we don't need to do any configuration change, correct me if I am wrong.

Thanks

-A

[bayupw]

Hi

As long as the Clusters are in the same Datacenter (vCenter Datacenter), you do not need to reconfigure DVS.

I did host & cluster movement / break for a couple of times before in a production environment.

The steps are:

1. Create new cluster in the same Datacenter.

2. Perform maintenance mode on the hosts that will be moved to new cluster.

3. Drag and drop the hosts from old cluster to new cluster.

4. Perform exit maintenance mode on the moved hosts.

5. Reconfigure HA Admission Control Policy.

6. Migrate or vMotion VMs as necessary

You do not need to configure DVS if you are planning to use same VLAN on those 2 Clusters.

You can also perform cross-clusters vMotion as long as they have access to same shared storage but you will need to enable EVC if they are belong to different CPU Series.

You can check the EVC/CPU Matrix here http://www.vmware.com/resources/compatibility/search.php?deviceCategory=cpu

Thanks,

Bayu

[john23]

Thanks for detailed explanation. Completely agree, in Same DC, we don't need to create any DVS as well.

VMs are not need to migrate is not requirement, Since even in different Cluster, still vlans and other physical configuration are same. So interaction between VMs will not at all impact.

Experts: Please share any experience which can be challenge in this

Thanks

-A

[vThinkBeyondVM]

I do fully agree with Bayu's suggestion.