vSAN 2-Node Configuration Guide

This guide walks through configuring a 2-node vSAN cluster with witness appliance using the partitioned WD_BLACK drives.

Prerequisites Completed

  • ✅ MS-A2 hosts configured with partitioned WD_BLACK drives
    • Partition 1: 400GB for cache tier
    • Partition 2: 3.4TB for capacity tier
  • ✅ vSAN witness appliance deployed on Mac Pro
  • ✅ Witness networking configured (192.168.10.20)
  • ✅ All hosts have vSAN VMkernel adapters on VLAN 30

Configuration Steps

Step 1: Add Witness Host to vCenter

  1. Access vCenter: https://vcsa.markalston.net
    • Username: administrator@vsphere.local
    • Password: Cl0udFoundry!
  2. Add Witness as Standalone Host:
    • Right-click on Home-Datacenter
    • Select Add Host…
    • Enter details:
      • Host: 192.168.10.20
      • Username: root
      • Password: Cl0udFoundry!
    • Click Next
    • Do NOT assign to any cluster
    • Complete the wizard

Step 2: Enable vSAN on Cluster

  1. Navigate to MS-A2-Cluster
  2. Go to Configure → vSAN → Services
  3. Click CONFIGURE VSAN button
  4. Select configuration type:
    • Two host vSAN cluster
  5. Click Next

Step 3: Configure Disk Groups

  1. In the vSAN configuration wizard:

  2. Disk Selection page:

    For esxi-ms-a2-01.markalston.net:

    • Cache tier: Select WD_BLACK partition 1 (400GB)
    • Capacity tier: Select WD_BLACK partition 2 (3.4TB)

    For esxi-ms-a2-02.markalston.net:

    • Cache tier: Select WD_BLACK partition 1 (400GB)
    • Capacity tier: Select WD_BLACK partition 2 (3.4TB)
  3. Click Next

Step 4: Select Witness Host

  1. Witness Host Selection:
    • Select: 192.168.10.20 from available hosts
    • The wizard will automatically configure it as witness
  2. Witness Disk Selection:
    • Select the 10GB cache disk
    • Select the 15GB capacity disk
    • These are pre-configured in the witness appliance
  3. Click Next

Step 5: Configure Fault Domains

  1. Fault Domain Configuration:
    • The wizard automatically creates two fault domains
    • FD1: esxi-ms-a2-01.markalston.net
    • FD2: esxi-ms-a2-02.markalston.net
    • Witness: Separate witness fault domain
  2. Click Next

Step 6: Review and Complete

  1. Review Configuration:
    • Cluster type: 2-node vSAN
    • Data hosts: 2 (MS-A2-01 and MS-A2-02)
    • Witness host: 1 (192.168.10.20)
    • Total capacity: ~6.8TB raw
    • Fault tolerance: 1 host failure
  2. Click FINISH to apply configuration

Step 7: Verify vSAN Health

  1. Navigate to MS-A2-Cluster → Monitor → vSAN
  2. Check Skyline Health:
    • All checks should be green
    • Pay attention to:
      • Network configuration
      • Disk health
      • Witness connectivity
  3. Check Capacity:
    • Should show ~3.4TB usable capacity (with FTT=1)

Expected Disk Configuration

MS-A2-01 (192.168.10.12) 

Disk Group 1:
  Cache Tier:    WD_BLACK 400GB partition (t10.NVMe...E929...00:1)
  Capacity Tier: WD_BLACK 3.4TB partition (t10.NVMe...E929...00:2)

MS-A2-02 (192.168.10.13) 

Disk Group 1:
  Cache Tier:    WD_BLACK 400GB partition (t10.NVMe...3C29...00:1)
  Capacity Tier: WD_BLACK 3.4TB partition (t10.NVMe...3C29...00:2)

Witness (192.168.10.20) 

Disk Group 1:
  Cache Tier:    10GB virtual disk
  Capacity Tier: 15GB virtual disk

Troubleshooting

Issue: Cannot claim partitioned disks

Solution: Ensure partitions have correct GUID:

# Check partition GUID (should be AA31E02A400F11DB9590000C2911D1B8)
partedUtil getptbl /vmfs/devices/disks/t10.NVMe____WD_BLACK_SN850X_4000GB__________________[SERIAL]

Issue: Witness not selectable

Solution:

  1. Ensure witness is added as standalone host (not in cluster)
  2. Verify witness has vSAN VMkernel adapter configured
  3. Check witness can ping MS-A2 hosts on vSAN network (VLAN 30)

Issue: Network partition detected

Solution:

  1. Verify all hosts can communicate on vSAN network (192.168.30.0/24)
  2. Check VLAN 30 is properly configured on all switch ports
  3. Ensure vSAN VMkernel adapters have correct IP addresses

Post-Configuration Tasks

  1. Create vSAN Storage Policy:
    • Navigate to Policies and Profiles
    • Create new VM Storage Policy
    • Set rules for vSAN (FTT=1, RAID-1 mirroring)
  2. Test VM Deployment:
    • Deploy a test VM to vSAN datastore
    • Verify it’s accessible from both hosts
    • Test vMotion between hosts
  3. Configure vSAN Alarms:
    • Review and enable appropriate vSAN alarms
    • Configure email notifications if desired

Performance Expectations

With this configuration:

  • Usable Capacity: ~3.4TB (after RAID-1 mirroring)
  • Cache Ratio: ~12% (400GB cache / 3.4TB capacity)
  • Read Performance: Near-NVMe speeds from cache
  • Write Performance: NVMe speeds (all-flash configuration)
  • Fault Tolerance: 1 host failure (either data host)

Monitoring Commands

SSH to MS-A2 hosts and run:

# Check vSAN cluster status
esxcli vsan cluster get

# View disk groups
esxcli vsan storage list

# Check network configuration
esxcli vsan network list

# Monitor performance
esxtop
# Press 'x' for vSAN statistics

References

Configuration Date: 2025-01-21
Environment: ESXi 8.0.3, vSAN 8.0.3

This project is for educational and home lab purposes.