Troubleshooting Hyper-V to Azure Replication Issues when using Azure Site Recovery

This article details some of the more common error messages encountered when replicating on-premises Hyper-V virtual machines using Azure Site Recovery and explains in detail the troubleshooting steps to resolve them.

Enable protection failed

Initial replication stuck (or) Replication not progressing

This can happen for various reasons listed below. It is always a good practice to ensure that you are running on latest agent (visit this article  and check the instructions of latest rollup update):

  • Check if the replication is Paused
    • Connect to the on-premises Hyper-V manager console, select the virtual machine, and see the replication health.
    • If replication health is Critical, right-click the virtual machine > Replication > View Replication Health.
    • If replication is paused, then click Resume Replication.
  • Check if the Azure Site Recovery services are running. (Re)Start any service, which is not running and check if the problem still exists.
    • Hyper-V to Azure: On the Hyper-V server:
      • Virtual Machine Management service
      • Microsoft Azure Recovery Services Agent
      • Microsoft Azure Site Recovery Service
    • Hyper-V with VMM to Azure:
      • On Hyper-V host, ensure "Virtual Machine Management service" and "Microsoft Azure Recovery Services Agent" is running
      • On VMM server, ensure  "System Center Virtual Machine Manager Service" is running
    • Ensure WMI Provider Host service is running on Hyper-V host.
  • Check your network bandwidth availability
    • Check if there are bandwidth or throttling constrains in your configuration by following steps and recommendations listed in this article.
    • Run the profiler (steps) using Deployment Planner tool. Follow bandwidth recommendations, storage recommendations and aware of data churn limitations.
  • Check connectivity between Hyper-V server to Azure: From Hyper V server, open the Task Manager (press Ctrl-Shift-Esc) -> Performance tab ->Open Resource Monitor-> Network tab. Check if cbengine.exe in ‘Processes with Network Activity’ is actively sending large volume (in Mbs) of data.
  • Check if Hyper-V server can connect Azure Blob:   Select and check cbengine.exe to view the 'TCP Connections' to see if there is connectivity from Process server to Azure Storage blob URL
  • High data churn on VM: 
    • Check if your VM is marked for resynchronization. One of the reasons this can happen, is if the HRL files reaches 50% of the available disk space. To investigate the source of churn follow steps listed in this article. If this turns out to be the issue, then provision more storage space for all VMs enabled for replication to Azure that are accounting for the HRL file growth.
    • Network bandwidth limitations can also impact replication. Follows steps listed under Check your network bandwidth availability section to ensure there is enough bandwidth to meet your requirements.
    • Ensure the replication is not paused. If the replication is suspended/paused, it does not stop writing the changes to the hrl file (which in turn can lead growth of HRL files reaching limit).
    • Choose the appropriate storage to match your churn scenario as listed in this article.




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