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
Note:
For successful restores from future incremental backups, run backups with the 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
InvalidorForeign.
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
InvalidorForeigndisk. - Enter select disk disk ### to select the disk that is
InvalidorForeign. - 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.