vSAN 2-Node Configuration on VxRail

VMware vSAN 2-Node Cluster is a configuration implemented in environments where a minimal configuration is a key requirement, typically in Remote Office and Branch Office (ROBO). A VMware vSAN 2-Node Cluster on VxRail consists of a cluster with two directly connected VxRail E560 or E560F nodes, and a Witness Host deployed as a Virtual Appliance. The VxRail cluster is deployed and managed by VxRail Manager and VMware vCenter Server.

A vSAN 2-Node configuration is very similar to a Stretched Cluster configuration. The Witness Host is the component that provides quorum for the two data nodes in the event of a failure. This vSAN 2-Node configuration includes two deployment architecture, i.e. the vCenter server and Witness host can locate in a main datacenter or same location. The following are the two options of deploying vCenter and Witness.

Remark: RTT between Witness and data nodes up to 500ms. Bandwidth of at least 1.5Mbps. Minimum VxRail software version is 4.7.100

2-Node Licensing Options for vSAN

Option A: vSAN ROBO license

  • Per-VM licensing model (Standard, Enterprise, Advanced editions)
  • Support total of 25 powered-on VMs in single location or across multiple locations

Option B: regular vSAN license

  • Deployments running more than 25 VMs
  • Per-socket licensing model

vSAN 2-node basics

  • Both nodes must be in a single physical location
  • Only supports PFTT=1, mirroring (VM objects are mirrored across two nodes, FTT=1)
  • Witness host required as the tiebreaker
  • 3 fault domains (Witness host included)
  • Can use either normal per-socket vSAN licenses or the per-VM vSAN ROBO licenses

Witness host

  • Virtual appliance running ESXi (multiple sizes depending on VM count)
  • Receives Witness traffic from the two nodes
  • must run outside of cluster and requires Witness traffic separation
  • Can run on a host within the same rack, but not in the 2-node cluster

vCenter and Witness host on separate server or cluster at a same site

  • Ports 1 and 2 for HA for ESXi management, VM network, and Witness traffic
  • Ports 3 and 4 for vSAN and vMotion directly connected to each other
  • Separate Witness management traffic from vSAN traffic
  • vCenter server cannot be installed in the same cluster

 

vCenter and Witness are locate in HQ datacenter.

7 thoughts on “vSAN 2-Node Configuration on VxRail

    • Only supports PFTT=1, mirroring (VM objects are mirrored across two nodes, FTT=1). The VM is still running in health if the impact of failure of one node. Best practice to run less than 50% of a nodes resource load, so a single node can bear full cluster load in case of a node failure.

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  1. hello i have problem.
    i’m deploying vxrail 2node cluster.
    but i got 2 error message.
    1. vsan cluster configuration consistency. – network configuration is out of sync2
    2. witness host not found.
    192.168.1.155
    ㄴ192.168.1.191<-witness
    192.168.1.110
    ㄴ 192.168.1.51<- venter
    ㄴ192.168.1.202vsan health alarm “witness host not found”
    >vsan cluster configuration consistency

    i checked all network configuration and ping.
    (like vmkping, esxcli network ip neighbor list -i vmk1)

    and vxrail 2node deploy was stopped at step 55.(Configuring storage policies on vcenter server)
    at the same time in vcenter’s recent task show me
    “invalid virtual machine configuration
    there are currently 2 usable fault domain the operation requires 1 more usable fault domain”

    I don’t know what problem caused this.
    I’ve been looking for the cause for two months from step 55.

    can you help me?
    if you need remote connection. i will support remote connection like team viewer.

    Like

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