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SAN (Disaggregated) Deployment

Runbook Azure Storage

DOCUMENT CATEGORY: Runbook SCOPE: SAN-based Azure Local cluster deployment PURPOSE: Deploy Azure Local using external SAN storage (disaggregated architecture) MASTER REFERENCE: Microsoft Learn — Deploy via Portal (Disaggregated)

Status: Active

Overview​

Starting with Azure Local 2604, you can deploy Azure Local using Storage Area Network (SAN) storage — a disaggregated architecture where compute and storage are independent. This is an alternative to the traditional hyperconverged model using Storage Spaces Direct (S2D).

Disaggregated deployments:

  • Support single machine to 64-machine clusters
  • Enable independent scaling of compute and storage
  • Use existing SAN infrastructure (Fibre Channel, or iSCSI from release 2607)
  • Share a unified management control plane via Azure Arc
iSCSI support

iSCSI-connected SAN storage was added in preview with release 2605 and became generally available in release 2607, for both hyperconverged (SAN alongside Storage Spaces Direct) and disaggregated deployments. Machine validation fails for disaggregated deployments that use SANs from unsupported vendors. The runbook tasks on this site cover Fibre Channel. For iSCSI, follow Connect an external storage array to Azure Local.

S2D vs SAN Comparison​

AspectStorage Spaces Direct (S2D)Storage Area Network (SAN)
ArchitectureHyperconverged — storage is local to compute nodesDisaggregated — external SAN provides storage
ScalingCompute and storage scale togetherCompute and storage scale independently
Max Nodes16 nodes64 nodes
StorageLocal NVMe/SSD/HDD in each nodeExternal SAN arrays via Fiber Channel
NetworkRDMA for storage traffic between nodesFC fabric for storage traffic to SAN
HardwareStandard servers with local drivesServers with FC HBAs + FC switches + SAN
Rack Aware✅ Supported (Rack aware clustering)❌ Not supported with external SAN storage
Use CaseGeneral purpose, smaller clustersLarge clusters, existing SAN infrastructure

Supported Fiber Channel Patterns​

Azure Local supports four disaggregated networking patterns:

PatternDescriptionReference
FC without backupFiber Channel SAN, no backup networkFC No Backup
FC with backupFiber Channel SAN with backup networkFC With Backup
FCoE without backupFiber Channel over Ethernet, no backupNetwork Patterns Overview
FCoE with backupFiber Channel over Ethernet with backupNetwork Patterns Overview

Prerequisites​

Hardware​

RequirementDetails
Validated hardwareFrom the Azure Local Catalog — disaggregated-validated SKUs
FC HBAsMinimum 2 per node (dual-path for redundancy)
FC switchesTwo independent fabrics for redundancy
SAN arrayExternal storage with FC connectivity
LUN minimums250 GB for infrastructure volume, 20 GB for cluster performance history

SAN Configuration (Before Cluster Deployment)​

The following must be completed after Arc registration but before starting the cluster deployment wizard:

  1. Install FC HBA drivers on each node:

    PNPUTIL /add-driver <path-to-driver>\*.inf /install

  2. Verify HBA ports are visible:

    Get-InitiatorPort

  3. Enable MPIO (Multipath I/O):

    Add-WindowsFeature Multipath-IO
    # Reboot required
    Enable-MSDSMAutomaticClaim -BusType "FC"

  4. Verify SAN disks are visible and in RAW state:

    Get-PhysicalDisk | Where-Object { $_.BusType -eq 'FibreChannel' }
Do Not Initialize Disks

SAN disks must remain in RAW state. Do not initialize, partition, or format them before cluster deployment. The deployment process handles disk initialization.

HBA Zoning After Arc Registration

Configure FC zoning (WWPN-based) after Azure Arc registration is complete. Zoning before registration can cause deployment confusion as LUN visibility may interfere with the Arc registration process.

Deployment Options​

IdentityMethodLink
Active DirectoryPortalAD — Portal (SAN)
Active DirectoryARM TemplateAD — ARM Template (SAN)
Local IdentityPortalLocal Identity — Portal (SAN)
Local IdentityARM TemplateLocal Identity — ARM Template (SAN)

Post-Deployment: Connect External Storage​

After cluster deployment completes, you must connect the SAN storage to the cluster. See Microsoft Learn — Connecting an External Storage Array for the full procedure, which includes:

  1. Verify SAN disks are visible on all nodes (Get-Disk)
  2. Initialize disks as GPT
  3. Create partitions and format as NTFS
  4. Validate cluster storage configuration (Test-Cluster)
  5. Add SAN volumes as Cluster Shared Volumes
  6. Create Storage Paths in the Azure portal
← Deployment Methods↑ Phase 05: Cluster DeploymentPost-Deployment →

References​

VersionDateAuthorChanges
1.02026-05-01Azure Local CloudInitial release — SAN (Disaggregated) deployment