HyperFlex Stretched Cluster Networking

[ShishirDash5204]

 Hello All ,

As the minimum network requirement for the two active site on a stretch cluster is 10Gbps and 5ms latency. So if I have 3 Stretch Cluster as shown in the topology . Do I need to have 3 dedicated 10 Gbps/ 5 ms latency for each cluster ? What is the recommended bandwidth between 2 sites?

[Kirk J]

Greetings.

https://www.cisco.com/c/en/us/td/docs/hyperconverged_systems/HyperFlex_HX_DataPlatformSoftware/HyperFlex_Stretched_Cluster/4-5/b-hx-systems-stretched-cluster-guide-4-5/m_preinstallation_checklist.html 

• 10 Gbps dedicated, 5-ms Round-Trip Time (RTT) latency between the two active sites is required. (PER stretch cluster)

• 100 Mbps, 200 ms-RTT worst case latency for 16 kilobyte packet sizes between the active sites and witness site is required.

With 3 clusters on one 10Gb link, you may run into issues with a single 10Gb link, as 3 clusters sharing the same 10Gb link during peak usage times may overwhelm it, resulting in drops, that would lead to latencies, etc.

Ideally, you want to have 3  independent, separate links, although I suppose  some sort of a PC of 3-4 10Gb links would probably keep the traffic distributed pretty well, and provide redundancy.

Might want to open a TAC case on that, that get clarification on your exact proposed config.

Kirk...

[ShishirDash5204]

Thanks for the clarification. Here in this case this is three actual stretch cluster with different number of nodes per cluster sharing the same pair of fabric interconnect . What would be the recommended bandwidth and latency? Does number of node count per cluster also have impact on the intersite link?. 

[Kirk J]

Consolidated responses below.