stretched cluster (Metro Availibility) questions

  • 10 February 2017
  • 1 reply

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My question is about the network connectivity of Nutanix nodes across two campus buildings. The objective is to create a four node cluster in building A and a four node cluster in building B. The buildings are about 2000 ft apart with dual fiber at 10Gbps Then with VMware ESXi create a stretch clsuter across all 8 nodes. That's part seems rather straight forward.

The questions are around network connectivity. In building A there is a core switch Cisco 6506 and an access layer Cisco Nexus 5548. In building B there is the same thing. The two core switches have 20 Gbps interconnect links and VSS. The Nexus 5548s are cross connected to the core and to each other, all with 20 Gbps each. The VSIs are on the Core.

Normally I would have two switches in the same building to redundantly connect each node to, but in this case I only have one 5548 available in each building. If I connect each node with one link locally to the 5548 then using a long range SFP in the server I connect the redundant link to the 5548 in the other building.

What problems will I have if I do this?
Is there a way to keep all traffic between all of the nodes in a particular building so that it does not involve the switch in the other building except when it is writing the data to the other four node cluster?

1 reply

Userlevel 4
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Hi jlosi

There is a way to force replication over a specified vNIC. As far as the remote 5548, could you put that uplink that connects to it in standby in the vSwitch configuration? Problem is, the other 5548 switch, port or line would have to fail in order for it failover. I wouldn't recommend this configuration. At least run two connections to the local 5548 and then a third to the remote if you can't get two more 5548's.