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Dell VxRail Network Planning Guide

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Switch considerations

Select one or two switches for the VxRail cluster. One switch is often used in test and development environments. Two or more switches are required to support sustained performance, high availability, and failover in production environments. More switch features and functionality may be necessary to support specific use cases or requirements.

Consider the following performance factors when considering switches:

  • If your plans include deploying all flash storage on your VxRail cluster, 10 GbE network switches are the minimum requirement for this feature. Use a minimum 25 GbE network if that is supported in your data center infrastructure.
  • Enabling advanced features such as L3 routing services on the switches for the VxRail cluster, may cause resource contention and consume switch buffer space. Select switches with sufficient resources and buffer capacity.
  • Switches that support higher port speeds are designed with higher Network Processor Unit (NPU) buffers. Use an NPU shared switch buffer of at least 16 MB for 10 GbE network connectivity. Use an NPU buffer of at least 32 MB for more demanding 25 GbE network connectivity.
  • For large VxRail clusters with demanding performance requirements and advanced enabled switch services, consider switches with additional resource capacity and deeper buffer capacity.

VxRail is an SDDC which relies on the physical ToR switching for network communications. VxRail is engineered to enable full redundancy and failure protection across the cluster. For environments that require protection from a single point of failure, design and configure the adjacent network supporting the VxRail cluster to eliminate any single point of failure. Deploy a minimum of two switches to support high availability and balance the workload on the VxRail cluster. Link the switches with a pair of cables to support the flow of L2 traffic between the switches.

Consider LAG to enable load-balancing and failure protection at the port level. NIC teaming, which is the pairing of physical ports into a logical port is supported in VxRail 7.0.130 and later. These logical port pairings can peer with a pair of ports on the adjacent switches to enable the load-balancing of demanding VxRail networks.
Figure 1. Multi-chassis LAG across two switches. Multi-chassis LAG across two switches
Multi-chassis link aggression across two switches

For network-intense workloads that require high availability, consider switches that support multi-chassis LAG, such as Cisco vPC or Dell VLT port channel. Multi-chassis LAG can be used to enable load-balancing from the VxRail cluster across a logical switch port that is configured between the two linked switches.

For VxRail 7.0.130 and later, LACP at the cluster level is supported. The switches supporting the VxRail cluster should support LACP for better manageability and broader load-balancing options.


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