Target datastore does not match the current VM policy during migration to vSAN Stretched Cluster

Products

• VMware vSAN

Issue/Introduction

Migration tasks from external environments, such as a Nutanix cluster, are blocked during datastore selection when moving virtual machines to a VMware vSAN Original Storage Architecture (OSA) Stretched Cluster. This occurs when the vSAN Placement Engine cannot satisfy the host requirements of the VM assigned storage policy within the destination local site.

 

Symptoms

• Error: "The target datastore does not match the current VM policy."
• Error: "Policy specified requires 3 hosts contributing all-flash storage, but only 2 found."
• Error: "0 all flash host found."

 

Environment

• VMware vSAN 8.x OSA
  
  
• SAN Stretched Cluster (2+2+1 or 3+3+1 configurations)
  
  
• Migration from external clusters (Nutanix/Other)

Cause

In vSAN Original Storage Architecture (OSA), RAID-5 Erasure Coding (FTT=1) requires a minimum of 4 fault domains (hosts). In a Stretched Cluster, the Local Fault Tolerance Method must be satisfied entirely within the local site. If a site only contains 2 data nodes (as in a 2+2+1 setup), the engine cannot place the 4 required components locally.

Resolution

To resolve this migration block, use one of the following methods:

Method 1: Adjust the VM Storage Policy (Recommended) Modify the storage policy to a setting compatible with the destination site's host count.

1. Change the Local Fault Tolerance Method from RAID-5 (Erasure Coding) to RAID-1 (Mirroring).
   
   
2. RAID-1 only requires 2 hosts per site, which is compatible with 2+2+1 or 3+3+1 topologies.
   
   
3. Retry the migration.

Method 2: Scale the Cluster Hardware

1. Expand the physical host count of the target vSAN cluster.
   
   
2. Ensure each site has a minimum of 4 data nodes (e.g., a 4+4+1 configuration).
   
   
3. Once the hardware is expanded, the RAID-5 policy will satisfy the placement engine rules.

Method 3: Configure Storage Tier Explicitly set the Storage Tier to "All-Flash" in the VM storage policy. Even on all-flash clusters, the error "Capacity requires All-Flash configuration" can occur if the policy Storage Tier is set to "No Preference" (Case 36854387).

Additional Information

Reference articles.

Clarification on vSAN "Fault domain failures to tolerate” as displayed under Cluster - Configure - Fault Domains

The host cannot enter maintenance mode. Resource check failed - vSAN 4-node cluster

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