HCX Bulk or RAV migration is stuck at 0% Base sync for a Virtual Machine

Products

• VMware HCX
• VMware vSphere ESXi

Issue/Introduction

• HCX bulk migration/RAV does not progress for one particular VM.
• The initial base synchronization remains at 0%, as confirmed in the HCX Manager(Connector or Cloud) logs located at /common/logs/admin/app.log
  

  2024-07-04 07:43:40.973 UTC [ReplicationTransferService_SvcThread-3515, Ent: HybridityAdmin, , TxId: TxId: <Transaction ID of the migration> WARN  c.v.h.s.r.j.ReplicationTransferMonitor- Current bytes transferred value 0 is not greater than the already transferred bytes value 0, hence not updating for transfer <UUID of migration ID>

• On the ESXi where the VM resides you would see this log message under /var/run/log/vmkernel log:
  

  2024-06-20T12:42:36.017Z cpu24:311746948)WARNING: Hbr: 4813: Failed to establish connection to [x.x.x.x]:31031(groupID=VRID-########-####-####-####-###########): Corrupt response from replication server

• The affected VM has more than 64 disks attached.

Environment

• VMware ESXi 7.x or 8.x
• VMware HCX

Cause

Maximum number of protected disks per virtual machine on ESXi 8.0 or earlier version is 64 as per Operational Limits of vSphere Replication

 

Resolution

• Upgrade ESXi to version 8.0 U1 or higher

OR

• Cancel the migration task for the affected VM
• Reduce the number of disks attached to the VM to 64 or less.
• Restart the migration task