How to Perform Cross-Platform Restore for CentOS VM (VMware to Hyper-V)

How to Perform Cross-Platform Restore for CentOS VM (VMware to Hyper-V)

KB ID: 115917

Overview

When restoring a CentOS VM, backed up from an ESXi server (VMware), to a Hyper-V server, the Instant Boot recovery fails, and the VM enters Shell Emergency mode during the recovery process on Hyper-V.

Steps to Resolve

Follow these steps on the Linux-based machine to resolve the issue and successfully restore the CentOS VM from VMware to Hyper-V.

1. Modify the Boot Image

Ensure the necessary drivers are included in the boot image by running the following command:
sudo dracut -f -v -N

2. Verify Hyper-V Drivers in the Boot Image

After modifying the boot image, confirm that Hyper-V drivers are present by running:
lsinitrd | grep hv
  1. If Hyper-V drivers are included, the output will list files or modules such as:
/lib/modules/4.15.0-123.el7.x86_64/kernel/drivers/hv/hv_vmbus.ko
/lib/modules/4.15.0-123.el7.x86_64/kernel/drivers/hv/hv_storvsc.ko
  1. If no output is returned, it indicates that Hyper-V drivers are missing, and further actions are required to include them.

3. Check and Modify dracut Configuration Files

  1. Verify that no dracut configuration files contain the line hostonly="yes", as this can restrict the drivers included in the boot image. Use the command:
grep -r 'hostonly=' /usr/lib/dracut/dracut.conf.d/
  1. If any configuration files contain hostonly="yes", edit them to set hostonly="no" to include all necessary drivers.

4. Perform Full Backup and Instant Recovery

After ensuring the correct drivers are included in the boot image:
  1. Perform a new full backup using the Backup and Disaster Recovery (BDR) system.
  2. Once the backup is complete, initiate Instant Recovery to the Hyper-V server.
The CentOS VM should now boot successfully without entering emergency mode.

Conclusion

By modifying the boot image, verifying the presence of Hyper-V drivers, and updating configuration files, you can resolve the issue of a CentOS VM entering Shell Emergency mode during Instant Boot recovery on Hyper-V. These steps ensure a smooth cross-platform restore from VMware to Hyper-V.