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Using Fibre Channel Storage with vSAN#

Overview#

VergeOS vSAN supports the use of Fibre Channel (FC) LUNs as storage devices within its tiered architecture. This enables seamless integration with your existing SAN infrastructure while benefiting from vSAN’s native performance, redundancy, and efficiency.

VergeOS Path Optimization

VergeOS automatically selects the best path for each LUN based on internal algorithms. It’s normal to see multiple disks with identical serial numbers in the UI—this does not indicate a problem.

Unique LUNs Per Node

Unlike traditional shared-storage clustering, VergeOS vSAN expects each node to be presented with its own unique LUN(s). Do not present the same LUNs to multiple nodes.

Path Management#

Multipath Configuration#

VergeOS manages multiple paths to each LUN in an active/passive configuration:

  • Primary Path – Used for I/O
  • Secondary Paths – Automatically activated on failure
  • Failover Timeout – 7-second delay before switching
  • Path Recovery – Alternate path remains active until manually overridden

Default Behavior

Multipathing is automatically enabled in VergeOS 4.13 and later.

Implementation Requirements#

Hardware#

  • FC Host Bus Adapters (HBAs) in at least two cluster nodes
  • Compatible FC switches (8/16/32 Gb)
  • FC storage array with available LUNs
  • Redundant FC fabric highly recommended

Fabric Configuration#

  • WWPN-based zoning configured
  • Each node is assigned dedicated LUNs
  • Redundant physical paths per node

One LUN Per Physical Disk

For maximum efficiency and to avoid duplicate redundancy, we recommend mapping each FC LUN to a dedicated physical disk.

Turn Off Storage Redundancy

VergeOS vSAN handles data redundancy and deduplication natively. You should disable RAID, deduplication, or tiering features on the SAN for LUNs used by VergeOS.

Configuration Steps#

  1. Prepare the FC Environment: - Set up WWPN zoning on the FC switch
    - Present unique LUNs to each node
    - Confirm multipath availability per node

  2. Add Storage to vSAN: - Open the Storage Tiers section in the VergeOS UI
    - Select the tier where FC LUNs will be added
    - Apply the configuration
    - Confirm that drives appear in the desired tier

Best Practices#

Path Management#

  • Use redundant physical connections per node
  • Test failover functionality regularly
  • Keep HBA firmware updated
  • Monitor path health proactively

Performance Optimization#

  • Distribute LUNs evenly across paths
  • Monitor queue depth and I/O throughput
  • Adjust HBA settings if needed
  • Avoid oversubscribing a single LUN with multiple VMs

Core Network Bandwidth Consideration

VergeOS vSAN uses the core network when reading/writing data. This means that during a write operation, the system sends the data to two nodes simultaneously over the core network. If your Fibre Channel SAN supports 32 Gb speeds but your core network is 25 Gb, the maximum write throughput will be constrained by the core network, not the SAN. To maximize performance, ensure the core network is greater than the FC SAN bandwidth, especially for write-intensive workloads.

Use Maintenance Mode

Always enter Maintenance Mode before modifying storage configurations.

Monitoring and Maintenance#

Troubleshooting#

Path Failures#

  • Check physical connections
  • Confirm FC switch zoning
  • Review HBA logs and driver status
  • Validate storage array health

Performance Bottlenecks#

  • Check queue depths and path load
  • Confirm proper multipath usage
  • Identify oversubscription of specific LUNs