About the Master Grid

A Master Grid is similar to an Infoblox Grid, except that the sole purpose of the Master Grid is to manage multiple Grids. It synchronizes status and IPAM information with its managed Grids, so you can view and manage data across multiple Grids from the Master Grid.
A Master Grid contains one Multi-Grid Master and one or more members. The Multi-Grid Master and its members can be single appliances or HA (High Availability) pairs. The Master Grid members cannot run any protocol, such as DNS or DHCP. Their only role in the Master Grid is that of Multi-Grid Master candidates. An appliance or HA pair that joins a Master Grid that already has a Multi-Grid Master automatically becomes a Multi-Grid Master candidate.
Communications between the Master Grid and its members are through an encrypted VPN tunnel, the same as in an Infoblox Grid. For details on Grid communications, refer to the NIOS Administrator Guide.
A Master Grid can include Infoblox appliances and vNIOS appliances. A vNIOS appliance is a non-Infoblox hardware platform running the vNIOS software package. You can configure Infoblox appliances and vNIOS appliances for VMware as Multi-Grid Masters or members. You can configure the other vNIOS appliances as grid members only. For information, refer to the Infoblox NIOS Administrator Guide.
NIOS and vNIOS appliances support different numbers of Grids. The maximum number of Grids that a Master Grid can support is based on the member with the lowest capacity. Note that when an appliance joins a Master Grid, the Multi-Grid Master checks if the platform type can support the number of currently managed Grids. If it cannot, then the join attempt is rejected.
The Multi-Grid Master is the only member in the Master Grid that runs the multi-grid management service that synchronizes data with the managed Grids. If the Multi-Grid Master is an HA pair, then the service runs on the active node only. If an HA failover occurs during a synchronization, the failing node immediately aborts the synchronization. The new active node resumes the next synchronization.
A Multi-Grid Master candidate does not run this service until it is promoted to Multi-Grid Master. The Multi-Grid Master replicates its database to all its members so that they have all the data they need in case of a candidate promotion. For more information about the Grid synchronization process, see /wiki/spaces/mgmadminguide/pages/911181989.
To connect to the Master Grid, you make a secure connection to Multi-Grid Manager. From Multi-Grid Manager, you can configure and manage the Master Grid.
Figure 5.1 illustrates the basic operations in multi-Grid management.

Figure 5.1 Grid Synchronization and Database Replication