A few days ago my colleague David Broome tested one of the new features, Metro Availability, in Nutanix Operating System (NOS) 4.1 that will be released next year. Yeah i know that time frame is a little bit vague but stay tuned beginning of next year year and you might have some more information:)

The NOS Metro Availability requires 2 Nutanix clusters , one at each site. The data replication is synchronous so we are not talking about disaster recovery (DR) which has been a feature in NOS for a long time.

This bog post presupposes that the Nutanix clusters are already in place since it will only cover the Metro Availability configuration and failover steps.

I’ll use the concept of primary and remote sites in this blog post even though both sites are up and running during normal operation just like in a traditional stretched cluster. The reason for primary and remote sites is that Nutanix Metro Availability is configured per Nutanix container and you need to define the roles per container. This means Site A can be primary and Site B remote for Nutanix Container 1 and Site A can be remote and Site B primary for Nutanix Container 2.

Configuration

Follow the below steps in Nutanix PRISM (UI) to setup Metro Availability

Create one Nutanix container at the primary site and one Nutanix Container at the remote site. Important to use the same Nutanix container on both sites.
Create the Remote Site mappings from the primary site via Data Protection -> Remote Site
Select the physical cluster, provide the Name and the IP for the remote site. Yes the first step is to create a DR configuration but hold on….

Advanced settings requires you to specify the Source and Destination containers and you can also specify maximum bandwidth and select compression on wire or not.
Create Metro Availability Protection Domain via Data Protection -> Add Protection domain -> Metro Availability
Type a name
Select the container you created the remote site mapping with
Select the Remote Sites mapping you created
Set VM Availability. This means what will happen in case the network connectivity disappear between the primary and remote site and you got two options:
- Stop the Metro Availability functionality automatically. Between 10-30 seconds are available options.
- Stop the Metro Availability functionality manually
Last step is to review your settings before creating the Metro Availability protection domain. A warning message about overwriting all data on the destination container is shown.

Failover

Four Metro Availability Protection Domains have been created for the purpose of this blog post.

Follow the below steps to failover Metro Availability Protection Domain CLS-Metro2 (protecting Nutanix container and vSphere NFS Datastore CLS2-Metro2) from Nutanix cluster gso-cluster2 to gso-cluster3.

Select the Metro Availability Protection Domain you want to failover and select Disable.
Answer yes to the popup warning regarding disabling the Metro Availability on CLS-Metro2.
Now when the Nutanix container is no longer active for the vSphere cluster we need to activate (enable read/write (R/W)) for the Nutanix container.
Go to the Nutanix cluster where you want to activate R/W -> select the disabled Metro Availability Protection Domain -> click Promote
Answer yes to the Promote Metro Availability popup question.
Metro Availability Protection Domain is active -> click Re-enable
Answer yes to popup about Re-enable Metro Availability for the Protection Domain which will overwrite data on the remote site.
The VMs running on the NFS Datastore we migrated from one site to another will experience a VMware HA event.