vSphere Storage Appliance requires a license key to operate. You can use the vSphere licensing infrastructure for VSA license management.

You can install and use vSphere Storage Appliance in evaluation mode. Evaluation mode supports multiple VSA datacenters. Before the 60-day evaluation period expires, you must assign an appropriate VSA license using one of the following licensing model.

vCenter Server Feature License
vSphere Essentials Plus includes vSphere Storage Appliance as a feature. Feature license supports a single VSA datacenter. When you use the feature licence, you must assign the Essentials Plus license to vCenter Server rather than VSA.
Note: After you assign the feature license to vCenter Server, the VSA asset might still appear as evaluation mode or might display as unlicenced, even though its licence is properly configured. You can verify the correct licensing information by clicking the vSphere Storage Appliance link on the VSA Manager page.
VSA Solution License
Certain vSphere editions support VSA as a standalone solution. With this type of license, you can have multiple VSA datacenters per vCenter Server instance. You assign a standalone VSA solution license to the VSA asset.

After the evaluation period passes, the VSA UI informs you that you can no longer manage your VSA clusters. If you have multiple VSA datacenters and want to continue using them, assign a valid VSA solution license key to the VSA licensing asset in vCenter Server. Otherwise, if you use a vCenter Server feature licence, delete additional VSA clusters to leave a single VSA datacenter.

The following table summarizes different licencing models available for vSphere Storage Appliance.

Table 1. VSA Licensing Models
vSphere Edition VSA License Type Number of VSA Datacenters
Essentials Not Supported
Essentials Plus Feature License

Assign to vCenter Server asset.

Single datacenter.
Essentials Plus ROBO Solution License

Assign to VSA asset.

Multiple datacenters.
Standard Solution License

Assign to VSA asset.

Multiple datacenters.
Enterprise Solution License

Assign to VSA asset.

Multiple datacenters.
Enterprise Plus Solution License

Assign to VSA asset.

Multiple datacenters.

For more information, see http://kb.vmware.com/kb/2059306.