This error can occur for the following reasons:

• The virtual machine and the alternate client virtual machine may contain too many disks. If the total is too great for the alternate client SCSI controllers, a backup with the hotadd transport mode fails. The following appears in the job status log: ERR - Error opening the snapshot disks using given transport mode: Status 23.

  Add more SCSI controllers to the alternate client virtual machine.

• If the VMware backup host cannot access the datastore over the selected transport mode, the backup fails. The detailed status log on the backup host may contain the following:

  12/4/2009 1:12:34 PM - Error bpbrm(pid=21376) from client vm4: ERR -
   Error opening the snapshot disks using given transport mode: Status 23.
  

  Select a different transport mode and retry the backup.

• For the backups that use the hotadd transport mode: The backup host was unable to resolve the host name of the ESX server. This error may occur if DNS is not correctly configured on the virtual machine where the backup host is installed. On the virtual machine, you can enter the IP address of the ESX server into the hosts file: \Windows\System32\drivers\etc\hosts

• For the backups that use the hotadd transport mode: If the virtual machine to back up and the virtual machine that contains the hotadd backup host do not reside in the same VMware datacenter, the backup fails. For a successful hotadd backup, the two virtual machines must be in the same VMware datacenter.

• A previous hotadd backup of the virtual machine may have failed. Certain mount directories or cloned disks must be manually removed to allow hotadd backups to succeed, as follows:

  • During a hotadd backup, VMware creates a linked clone of the virtual machine's disks and attaches the cloned disks to the backup host. (The attached disks can be seen in the vSphere Client interface.) If a hotadd backup of the virtual machine fails, NetBackup may be unable to remove the cloned disks from the backup host. In the backup host, the presence of the cloned disks prevents subsequent backups from completing.

    Remove the cloned disks from the VMware backup host and retry the backup.

  • During a virtual machine backup, VMware creates mount directories in the C:\Windows\Temp folder on the backup host. After the backup, VMware automatically removes the mount directories. In some cases, such as when the backup uses the hotadd transport mode, NetBackup may be unable to remove the mount directories.

    Remove the mount directories from the \Temp folder and retry the backup. The folder name contains a string such as VMware-System.

A virtual machine restore may fail in the following cases:

• If an .ISO file was presented to a virtual machine as a virtual CD or DVD during backup, note: The ISO file must be available on the destination host. If the ISO is not available on the host where you restore the virtual machine, the restore fails. The vCenter interface may include the message Invalid configuration for Device '1'.

• For restores that use the hotadd transport mode: If the virtual machine to restore and the virtual machine that contains the hotadd restore host do not reside in the same VMware datacenter, the restore fails. For a successful hotadd restore, the two virtual machines must be in the same VMware datacenter.

• For vStorage: The restore host cannot access the VMware datastore over the selected transport mode. The job log on the restore host may contain messages such as the following:

  FTL - Virtual machine restore: VxMS initialization failed
  

  Select a different transport mode and retry the restore.

• You attempted to restore a file that has a path name longer than 1023 characters.

  Note that a backup of a Linux virtual machine backs up all files, including those with path names longer than 1023 characters. A restore of the entire Linux virtual machine recovers all files. But you cannot restore the long path-name files individually.

• If the ESX servers are configured with short host names (not fully qualified), NetBackup may not find the ESX server for the restore.

  See The restore fails if ESX servers use short host names and backups and restores use a vCenter server.

• For the restore, the virtual machine's hardware version (such as 7) is later than the hardware version that the target server supports. If VMware Tools cannot convert the virtual machine's hardware version to an earlier version, the restore fails. Messages similar to the following appear in the bpVMutil log:

  createVMwareVM: Create virtual machine failed for host.com with 6
  

  If possible, restore the virtual machine to a VMware server that supports the virtual machine's hardware version.

• To restore a virtual machine in a datastore cluster and retain its DRS configuration, the target server must have the VMware "Storage DRS" and "Profile-Driven Storage" licenses. If the target server does not have those licenses, the restore fails.