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Veritas NetBackup™ for VMware Administrator's Guide

Last Published: 2019-06-28

Product(s): NetBackup (8.2)

For a VMware virtual machine with Windows dynamic disks, a restore from incremental backup fails with a Windows restore host and the hotadd transport mode

A restore of a Windows virtual machine by means of the hotadd transfer mode may fail in the following case:

A backup is taken of a Windows virtual machine that has a dynamic disk group.
After the backup, another dynamic disk is added to the virtual machine's disk group.
After the dynamic disk is added, an incremental backup is taken of the virtual machine.
A Windows restore host is used with the hotadd transport mode to restore the virtual machine from the incremental backup.

The restore fails when the Windows restore host tries to mount the dynamic disk that was added after the first backup. Depending on the data that has already been restored, Windows may detect the dynamic disk as Invalid or Foreign. Further writes to an Invalid or Foreign disk are unsuccessful and the restore fails.

The restore fails with status 1, "the requested operation was partially successful." Messages similar to the following may appear in the VxMS provider logs:

14:10:18.0854 : vdWrite:../VixInterface.cpp:760 <ERROR> : Error
24488361628532739 in write with vdhandle 48870608 startsector 
128 numsectors 1 14:10:18.0854 : write:VixFile.h:333 <ERROR> 
: Returned error 3, offset 0x0000000000010000, length 
0x0000000000000200   14:10:18.0854 : write:VixFile.h:334
<ERROR> : Returning: 11
 14:10:18.0854 : vixMapWrite:../VixCoordinator.cpp:1259 <ERROR> 
: Returning: 11
14:10:18.0854 : vix_map_write:../libvix.cpp:1826 <ERROR>
: Returning: 11

When they are enabled, VxMS logs are written in the following directory:

Windows:

install_path\NetBackup\logs\vxms

Linux:

/usr/openv/netbackup/logs/vxms

See Configuring VxMS logging.

Note:

For successful restores from future incremental backups, run backups with the Use Accelerator option in the policy.

Try any of the following workarounds to restore from the current incremental backup:

Use a Linux restore host (not Windows).
Use a different transport mode, such as NBD, NBDSSL, or SAN (not hotadd).
When the dynamic disk (the one that was added after the first backup) is mounted for restore, manually set the disk to offline. When the disk is offline, NetBackup can write data to it and successfully complete the restore.
See the remainder of this tech note for assistance with this workaround.

To determine when the dynamic disk is mounted for restore

Use the Windows Disk Management utility (Control Panel > Administrative Tools > Computer Management > Disk Management), or run diskpart in administrator mode and enter the list disk option.
When Windows attempts to mount the disk, it labels the disk as Invalid or Foreign.

To use diskpart to take the dynamic disk offline

On the Windows restore host, run diskpart in administrator mode.
Enter list disk to list all disks and find the Invalid or Foreign disk.
Enter select disk disk ### to select the disk that is Invalid or Foreign.

Enter offline disk to offline the disk.

Example session:

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          100 GB  1024 KB
  Disk 1    Online          256 GB    56 GB        *
  Disk 2    Invalid          40 MB    40 MB   *    *
  Disk 3    Offline          40 MB    40 MB

DISKPART> select disk 2

Disk 2 is now the selected disk.

DISKPART> offline disk

DiskPart successfully taken offline the selected disk.