vSphere Container Storage Plug-in supports volume provisioning on a preferential datastore.

You can use this functionality in an environment with a replicated datastore that is shared across two topology domains, or sites. The datastore is active in one of the topology domains, and is passive in the other.

When a site failure occurs, the active datastore on the failed site becomes passive, and the passive datastore on the other site becomes active.

In the following diagram, the DS-1 datastore is active in Site 1 and passive in Site 2. The DS-2 datastore is active in Site 2 and passive in Site 1.

Both datastores, DS-1 and DS-2, are accessible to all nodes in both sites. A typical volume provisioning request for Site 1 would provision a volume on either DS-1 or DS-2.

You can set preference to a particular datastore for a site, so that volume provisioning is limited only to the active datastore.

The diagram show the DS-1 datastore as active in Site 1, and DS-2 as active in Site 2. Both datastores are designated as preferred.

In this example, the DS-1 datastore is set as a preferred datastore for Site 1 and DS-2 datastore is a preferred datastore for Site 2.

To set preferential datastores for sites, follow these steps.

Procedure

  1. As a vSphere administrator, create a category with the following name:
    cns.vmware.topology-preferred-datastores.
  2. Create tags under this category that match the tags that you used for the topology domain name. For example,
    • For Site 1, if the topology domain name is site-1, create a site-1 tag under the cns.vmware.topology-preferred-datastores category.
    • For Site 2, if the topology domain name is site-2, create a site-2 tag under the cns.vmware.topology-preferred-datastores category.
  3. Assign the site-1 and site-2 tags created under the cns.vmware.topology-preferred-datastores category to the DS-1 and DS-2 datastore correspondingly.

Results

After you set the preference on the datastores, any volume provisioning request for site-1 ensures that the volume is allocated on the DS-1 datastore.