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Druva Documentation

Limitations to VMware virtual machine backup

Phoenix Editions: File:/tick.png Business File:/cross.png Enterprise File:/tick.png Elite

Phoenix performs a back up of all the configured virtual machines in your VMware setup, except in cases where VMware has its own limitations.


The limitations are as follows:

  • If you have suspended any virtual machine and configured it for backup in Phoenix, Phoenix does not back up such a virtual machine.
  • Phoenix deletes the manually created snapshots named PhoenixBackupSnap or PhoenixTempSnap when the Phoenix backup proxy performs the first backup of the virtual machine. 
  • Phoenix supports vRDMs. However, it does not support raw disks, RDM physical mode disks (pRDM), independent disks, or virtual machines that are configured with bus-sharing. 
    Note: This behavior is aligned with the default behavior of VMware, whereby snapshots of raw disks, RDM physical mode disks, independent disks, or virtual machines configured with bus-sharing are not supported.
  • If you set up a new vCenter to replace an old one, and do not assign the IP address from the old vCenter to the new one your backups will fail.
    For example, you deploy a backup proxy on vCenter server "A" with IP address Later on, you get a vCenter with a new version, and start a vCenter server "B" using it. Your network infrastructure assigns a new static IP to vCenter server "B". Now, you detach all your ESXi hosts from vCenter "A" and attach them to vCenter server "B", and shut down vCenter "A". Now, when a backup is triggered, your backups fail because Phoenix cannot locate the vCenter. To resolve this issue, before you shut down vCenter "A", assign an unused IP address like to vCenter "A". This frees the IP address Now, assign the IP address to vCenter "B" and provide vCenter credentials again in Phoenix Management Console.
  • If the backup proxy is unencrypted, and the virtual machine that is getting backed up through HotAdd is encrypted:
    • Transport mode is changed to NBDSSL, and the virtual machine is backed up successfully
    • When you restore the virtual machine, it is restored as an unencrypted virtual machine.
  • VMware does not let you select networks for both network interface cards at the time of deployment. The backup proxy is deployed with default network selected for both network interface cards. You can change the network for a card after the backup proxy is deployed using vSphere or web client. 
  • You cannot use all four DNS server addresses if:
    • You have enabled both network interface cards in the backup proxy
    • Both cards are configured to use different networks
    • Both cards use two domain naming systems each

    Due to Phoenix backup proxy limitations, when you add DNS server addresses, three out of four DNS addresses are used based on the sequence of network interface cards you configure.