Sync timeout for replication occurring in VMware Cloud Director Availability

Products

• VMware Cloud Director
• VMware Cloud Director Availability - Disaster Recovery 4.x
• VMware Cloud Director Availability - Migration 4.x

Issue/Introduction

• When synchronizing a protection or migration from a cloud environment to an on-premise environment in VMware Cloud Director Availability, the task fails with an  error similar to the following:
  
  Sync timeout for replication 'C4-########-####-####-####-############'
  
  
• In the replicator logs (/opt/vmware/h4/replicator/log), errors to similar to the example below can be found:
  
  

  2025-07-02 21:15:37.541 DEBUG - [########-####-####-####-############] [hbr-poller3] c.v.h.r.m.hbr.HbrGroupCollector          : Received an hbr error during the monitoring

  com.vmware.vim.binding.hbr.replica.fault.StorageNotAccessible: Error for (datastoreUUID: "########-####-####-####-############"), (diskId: "H4D-########-####-####-####-############"), (pathname: "_H4-########-####-####-####-############/example.vmdk"), (flags: on-disk-open): No accessible host for datastore '########-####-####-####-############'; Code set to: Storage was not accessible.; Failed to find host to get disk type; While getting host capabilities for disk. (native snapshot hint =  false); Failed to open disk, couldn't get disk type/capabilities; Set error flag: on-disk-open; Failed to open replica (/vmfs/volumes/########-####-####-####-############/_H4-########-####-####-####-############/example.vmdk); Failed to open activeDisk (GroupID=H4-########-####-####-####-############) (DiskID=H4D-########-####-####-####-############); Can't create replica state (GroupID=H4-########-####-####-####-############) (DiskID=H4D-########-####-####-####-############); Cannot activate group. Loading disks from database (GroupID=H4-########-####-####-####-############) ; Connecting to group H4-########-####-####-####-############
  ...

• The on-premise appliance is on a version lower than 4.7.3.
• The on-premise vCenter server is on a version of 8.0.3.

Environment

VMware Cloud Director Availabiity 4.7.x

Cause

Versions of VMware Cloud Director Availability (VCDA) below 4.7.3 are not compatible with any version of vSphere 8.0 U3. Moreover, vSphere 8.0 U3b is required, at a minimum, to be compatible with VCDA.

Resolution

Update VCDA to version 4.7.3 or higher and confirm that vSphere is on 8.0 U3b or higher.

Additional Information

For more information regarding compatibility between VCDA and vSphere, please refer to the following resources:

VMware Cloud Director Availability 4.7.3 Release Notes

Product Interoperability Matrix

For additional details on upgrading VCDA, please review the following document:

Upgrading on-premises and provider site