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Druva Documentation

VM becomes unresponsive during a snapshot removal

This article applies to:

  • Product edition: Phoenix

Problem description

Virtual Machine (VM) becomes unresponsive only during the snapshot removal operation after the Phoenix backup.

Cause

If the target VM is on an NFS datastore, the VM might become unresponsive when if the backup appliance mounts the virtual disk using HOTADD on the backup host and NFSv3 protocol is used to mount the datastores.

A limitation in the NFSv3 locking method causes a lock timeout that pauses the VM being backed up. This is a VMware limitation. 

Resolution

Upgrade the NAS array version to NFSv4 as a permanent fix.

Workaround

To use the NBD transport mode as a default (until NAS array is upgraded to NFSv4),  keep the Phoenix proxy running or configured and run the following steps:

  1. Stop the Phoenix service.

    /etc/init.d/Phoenix stop
  2. Verify if any Phoenix processes are still running.

    ps -ef\ grep -i Phoenix
  3. Go to /etc/Phoenix/VMWARE and edit Phoenix.cfg file using vi Editor. Add the following line to the configuration file.

    _VM_BACKUP_TRANSPORT_MODE = 'nbdssl:nbd'
  4. Save the configuration (.cfg) file.
  5. Start the Phoenix services.

    /etc/init.d/Phoenix start