Objective 3.1 – Identify Physical Network Requirements
All flash vSAN configurations require 10Gb network connectivity. 1Gb connections are supported for hybrid configurations although 10Gb is recommended. vSAN 6.6 simplifies design and deployment by removing the need for multicast network traffic (required for versions of vSAN prior to 6.6). When upgrading from a previous version of vSAN to vSAN 6.6, multicast is required until all hosts in the cluster are running version 6.6. vSAN automatically changes to unicast once the upgrade is complete.
Below is a slide I re-made from Cormac Hogan VMworld 2017 session.
| Minimum NIC Requirements for vSAN Networking | |||
| 10GB+ Support | 1GB+ Support | Comments | |
| Hybrid Cluster | Y | Y | 10Gb min recommended, but 1Gb supported <1ms RTT |
| All-Flash Cluster | Y | N | All flash requires 10Gb min, 1 Gb not supported <1ms RTT |
| Stretched Cluster (Data to Data) | Y | N | 10Gb required between data sites, <5ms RTT |
| Stretched Cluster (Witness to Data) | Y | Y | 100Mbps connectivity required from data sites to witness. <200ms RTT |
| 2-node Data to Data | Y | Y | 10Gb min, required for all-flash. 1Gb supported for hybrid, but 10G reco. |
| 2-node Witness to Data | Y | Y | 1.5 Mbps bandwidth required. <500ms RTT |
The network infrastructure for a vSAN environment should be designed with the same levels of redundancy as any other storage fabric. This helps ensure desired performance and availability requirements are met for the workloads running on vSAN.
WAN connectivity between the witness host and its 2-node or stretched cluster configuration is common. The throughput requirement for the connection between a witness host and the rest of the cluster is small to help minimize network connection costs.
Witness host network traffic can be separated from the network that connects the physical hosts in a 2-node cluster. This configuration option reduces complexity by eliminating the need to create and maintain static routes on the physical hosts. Security is also improved as the data network (between physical hosts) is completely separated from the WAN for witness host traffic.
Network Connectivity – IPv6
vSAN can operate in IPv6-only mode
- Available since vSAN 6.2
- All network communication are through IPv6 network
vSAN supports mixed IPv4 & IPv6 during upgrades only
- Do not run mixed mode in production.
Distributed or Standard Switch?
vSphere Standard Switch
- No management dependence on vCenter
- Recovery is simple
- Prone to mis-configuration(s) in larger setups
vSphere Distributed Switch
- Consistency
- Teaming and Failover (LACP/LAG/Ether-channel)
- Network I/O Control
- Comes with vSAN (Free)
Objective 3.2 – Configure vSAN Networking
Objective 3.3 – Configure a vSAN Cluster