VMware HCX Bulk Migration Error: "Replication is not enabled for the transfer"

Products

• VMware HCX

Issue/Introduction

During VMware HCX Bulk migrations, users may encounter the error message "Replication is not enabled for the transfer." This error manifests after the base synchronization has completed and while the virtual machine is in "waiting for maintenance window" status. The error typically appears after the migration remains in the waiting state for an extended period, commonly several days.

Environment

• VMware HCX
• Source and target vSphere environments
• HCX migration configurations with scheduled maintenance windows

Cause

Several factors can contribute to this replication error

1. Replication Configuration Persistence
   • The primary issue appears to stem from the replication configuration becoming invalidated or lost during extended maintenance window wait periods
   • The Host-Based Replication (HBR) manager loses the replication state information necessary for the transfer
2. Time-Based Degradation
   • Extended periods between base sync completion and maintenance window execution appear to increase failure likelihood
3. Infrastructure Communication
   • HBR manager communication between source and target environments may become interrupted
   • Replication service states between HCX components might become desynchronized
   • Network connectivity or infrastructure changes during the extended wait period could impact replication services
4. Resource Management
   • System resources allocated for replication might be released or reallocated during extended wait periods
   • Memory states and disk snapshots maintaining replication configuration could be affected by system maintenance or resource constraints
   • Background processes or system operations might interfere with replication persistence

Evidence in app.log typically shows multiple related errors when searching for the migration id

• "Error while getting progress details from HBR manager for the transfer"
• "Replication is not enabled for the transfer <migrationid>"
• "Replication config error has been in place for the transfer <migrationid> since 0 seconds"
• "Error Syncing Progress for <migrationid>"

Resolution

To successfully complete migrations, use the following strategy

1. Immediate Recovery Actions
   • Cancel failed migration attempts
   • Reinitiate the migration process for affected virtual machines
   • Adjust maintenance window scheduling to minimize wait time after base sync
   • Execute switchover operations promptly after base sync completion
   • Monitor replication status actively during the migration process
2. Preventive Measures
   • Plan maintenance windows to align closely with base sync completion
   • Structure migration batches to allow for immediate switchover after synchronization
   • Implement shorter intervals between base sync and switchover operations
   • Consider breaking large migration groups into smaller, manageable batches
3. Best Practices for Future Migrations
   • Schedule maintenance windows within 24-48 hours of expected base sync completion
4. Troubleshooting and Support
   • If migrations fail a second time
     
     • Monitor network connectivity between source and target environments
     • Document exact timing of base sync completion and error occurrence
     • Open a support case with Broadcom providing
       
       • Detailed environment information
       • Upload HCX and ESX logs for analysis
       • Migration IDs and screenshots of the failed migrations
       • Timeline of error messages and system changes
       • Any relevant infrastructure changes or maintenance activities

Note: Evidence has shown that migrations completed with minimal delay between base sync and switchover have a higher success rate. When implementing these solutions, prioritize reducing the time gap between synchronization completion and final switchover execution.