Select Primary Node
You can manually assign a storage appliance as the primary node for a grid. The job of the primary node is as an event communication hub to keep all the nodes up to date as their status and configuration changes. If the primary node is turned off you can continue to use the various appliances by logging into them directly, but configuration changes won't be reflected as the various appliances change until a new appliance is elected as a Primary. If you set a virtual IP address for the grid it will appear as something like "eth0:gridIP" and when that is present the system will automatically elect a new master node for you in the event that the current master node is disabled or turned off.
Navigation: Storage Management --> Storage System --> Set Master Node --> Storage System Grid --> Set Grid Master (toolbar)
For further information see Admin Guide - Grid Configuration