VxRail supports a solution specifically for small-scale deployments with reduced workload and availability requirements, such as those in a remote office setting. The solution is fixed to two VxRail nodes only, and like the stretched-cluster solution, requires a third site to act as a witness for monitoring purposes.
If you plan to deploy 2-node VxRail clusters, note the following:
- The minimum VxRail software version for the 2-Node cluster is 4.7.100.
- The deployment is limited to a pair of VxRail nodes.
- You cannot expand to three or more nodes unless the cluster is running version 7.0.130 or later.
- Verify that your workload requirements do not exceed the resource capacity of this small-scale solution.
- Only one top-of-rack switch is required.
- Four Ethernet ports per node are required. Supported profiles:
- 2 x 1 Gb and 2 x 10 Gb
- 4 x 10 Gb
- 2 x 25 Gb
- The switch can support either 1 GbE or 10 GbE connectivity.
- Two network topologies are supported for inter-cluster VxRail traffic:
- All four network ports connect to the top-of-rack switch
- A pair of network cables connect to create two links between the physical nodes, and the other two network ports connect to the top-of-rack switch
- A customer-supplied external vCenter is required. The customer-supplied external vCenter cannot reside on the 2-Node cluster.
- The Witness is a small virtual appliance that monitors the health of the 2-Node cluster. A Witness is required for the 2-Node cluster.
- An ESXi instance is required at the Witness site.
- Up to 64 2-node clusters can share a witness, provided the VxRail version is 7.0.100 or later. There is a 1:1 ratio of Witness per 2-Node cluster for previous versions.
- Witness can be deployed at the same site as the data nodes but not on the 2-Node cluster.
- For instances where there are more than one 2-Node clusters deployed at the site, the Witness can reside on a 2-Node cluster it is not monitoring. This configuration requires a VMware RPQ.
- The top-of-rack switch must be able to connect over the network with the Witness site.
Figure 15. 2-Node Cluster Topology with direct connections between nodes
Like the vSAN stretched-cluster feature, the small-scale solution has strict networking guidelines, specifically for the WAN, that must be adhered to for the solution to work. For more information about the planning and preparation for a deployment of a 2-node VxRail cluster, see the Dell EMC vSAN 2-Node Cluster Planning and Preparation Guide.