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NetVault Plug-in for VMware 12.0 - Release Notes

Resolved issues

Corrected an issue that prevented a backup selection at a Resource Pool level from backing up virtual machines in the pool.

DNVMWARE-1043 (22030)

Corrected an issue for non-Changed Block Tracking (CBT) users that caused an “Invalid service instance content” message to appear during the backup process.


Corrected an issue in which a backup job that included a significant number of files resulted in a stack overflow error during file-level indexing.


Corrected an issue that caused the plug-in to stop working while opening a 2 terabyte (TB) disk using network block device (NBD) mode.


Corrected an issue that caused the plug-in to stop working while reading an NTFS partition during a file-level backup.


Corrected an issue that caused a “Failed to get the inventory information for server” message to appear during a restore job to recover a deleted virtual machine.


Corrected an issue that prevented the plug-in from restoring a standalone VMware ESXi Server 6.5 virtual machine to VMware vCenter 6.0 or 6.5.

DNVMWARE-1698 (32475)

Corrected an issue that prevented the Quiesce VM for snapshot option from being saved in the Backup Preferences dialog box and applied to all backup jobs.


Corrected an issue that made disks that were excluded from a backup available for restore.


Corrected an issue that caused a backup job to stop responding when the targeted virtual machine was using VMware vCenter 5.5 Update 2. Also corrected the issue that prevented the cleanup process from releasing the lock.


Corrected an issue that caused the plug-in to stop working when multiple backup jobs ran simultaneously.


Corrected an issue that caused an out-of-bounds error to occur while reading disks of 2.7 TB or larger.


Corrected an issue that prevented a restore job from completing and displayed “Unexpected element sharing” and “Failed to add VM to target server's inventory” messages.


Known issues

When restoring data to an alternate datastore, the plug-in does not verify whether the datastore is available. Verify that the datastore is valid and has sufficient disk space to accommodate the virtual machine.

DNVMWARE-18 (1714)

Raw Device Mapping (RDM) disks in virtual compatibility mode are restored to flat “.vmdk” files and not to the original RDM. The alternative is to omit these disks during a restore.

DNVMWARE-332 (2371)

The configuration setting [Custom:MountOperationTimeoutSecs], which is stored in the vmware.cfg file, determines how long the plug-in process waits for the mount daemon to respond to a request. The default value is set to 600 seconds during a fresh install and 300 seconds during an upgrade. If the mount daemon is unable to complete a request within the specified interval, the virtual machine is left in a mounted state.

If you have many backups running simultaneously or your server is running under heavy load, modify the value for the [Custom:MountOperationTimeoutSecs] setting to avoid this issue.

DNVMWARE-505 (3131)

Virtual Disk Development Kit (VDDK) does not support non-UTF8 locales. On Linux-based clients that use non-UTF8 locales, the plug-in reports the error “Child Process died unexpectedly” and exits abnormally.

DNVMWARE-584 (3340)

When you use the NetVault Backup Plug-in for Consolidation, the image-level backups of virtual machines are displayed on the Create Selection Set page, but you cannot consolidate these savesets.


(6598, NVG-5474)

When you browse a localized virtual machine from an X11 or Motif GUI, the encoding of the name can cause the display to be scrambled or to not display at all.


(13679, VMW-157)

You cannot back up virtual machine templates using the Plug‑in for VMware.

Workaround: Convert the template to a virtual machine.


(13728, VMW-202)

To avoid file fragmentation, the Plug‑in for VMware preallocates disk space before restoring files to disk. On Linux-based systems, files that are larger than 50 MB in size are not pre‑allocated full disk space. Such files are handled similar to sparse files and allocated disk space as needed during restore. If the disk does not have sufficient space to fully restore files that are larger than 50 MB in size, the job fails when the disk runs out of space.

DNVMWARE-961 (21755)

The file-level indexing process does not generate indexes for symlinks.

DNVMWARE-977 (21793)

The file-level indexing process does not treat hard links in any special way and generates index entries for them as if they are separate entities. When you restore a saveset that includes a hard link, the plug-in stops responding.

DNVMWARE-978 (21794)

When using the NBD transport mode with VMware vSphere 5.1, a large Read Block Size may prevent multiple backup processes from running at the same time.

Workaround: Use SAN or SCSI HotAdd transport modes or decrease Read Block Size.

DNVMWARE-1430 (28815)

When restoring NTFS sparse files, if the actual allocated size of a data run is smaller than the total size of the data run, the restored file might be corrupted.

DNVMWARE-1456 (29043)

If the Diagnose Virtual Machine method is unable to return any result within the timeout interval (five minutes), the Web Service process displays the following message: “Error: The remote machine: <Name of the NetVault Backup Server> is unavailable”

You can close this dialog box to continue the current operation. In the background, the Diagnose Virtual Machine method runs the cleanup process to remove any snapshot that it has created.

DNVMWARE-1528 (29795)

Backups that have Active Block Mapping (ABM) enabled might stop working when memory is exceeded.


Backing up a virtual machine succeeds if the Virtual Machine Disk (VMDK) fails to open and the Exclude data disks option is selected.


The plug-in is unable to restore a virtual machine protected by VMware vSphere Fault Tolerance (vSphere FT) to an alternate VMware vCenter Server.

DNVMWARE-1691 (32398)

Installing an update of the plug-in puts the VMware Vstor2 MntApi driver into an inconsistent state.


If you are using a Windows-based proxy server, restart the server after you remove a VDDK. If you try to install or remove the VMware Vstor2 MntApi driver without restarting the server, you might encounter an error. For more information, see

Before installing the latest version of the plug-in, complete the following steps:

DNVMWARE-1697 (32473)

Support of virtual-machine encryption became available starting with vSphere 6.5; however, the plug-in does not support backup and restore of encrypted disks.


Clearing subnodes to exclude them from a backup job for a primary node causes the job to fail. If you select the main node, such as Datacenter, and then clear one or more of the subnodes, such as a node for a specific virtual machine or folder, the backup job fails and displays a “No virtual machines selected for backup” error message.


Restoring a virtual machine from a VMware vCenter Server 6.7 to an alternate vCenter Server 6.0, vCenter Server 6.5, VMware ESXi Server 6.0, or ESXI Server 6.5 fails. Although the hardware version is compatible, the following error is displayed: “Failed to add virtual machine to target server's inventory.”


Restoring a virtual machine on a VMware Virtual Volumes (VVol) datastore uses the storage policy associated with the VVol instead of using the storage policy associated with the backup.


When backing up a powered on virtual machine through a VMware vCenter Server, the plug-in may fail to back up the “.nvram”, “.vmx”, and “.log” files. For more information, see


When a snapshot is created on a virtual machine that uses thin-provisioned disks, VMware vSphere (the client and the underlying disk library) identifies the disk as thick. For more information, see


At the time of enabling CBT for a virtual machine, no snapshots must exist on it. For more information, see


If an ESXi 5.x host is managed by a vCenter Server, the virtual machines should not be restored when connected directly to the ESXi host. This restriction is due to a feature introduced in vSphere 5. For more information, see


To prevent the migration of a virtual machine while its disks are being accessed for a backup or restore, the plug-in uses VDDK APIs to lock and unlock a virtual machine. This functionality is disabled by default. To enable it, see the user's guide for the plug-in. Currently, the locking functionality has the following known issues:

Unlocking is known to fail occasionally. This issue has been documented in the VDDK 5 release notes. For details, review the “EndAccess sometimes does not reenable migration after PrepareForAccess” section in the VDDK 5.0 Release Notes.


VDDK 5 issues:


On a Windows 2012 virtual machine, data corruption may occur during or after a network copy operation. For more information, see


If the size of a virtual drive is 2 terabytes (TB) or a multiple of 2 TB, the disk is always opened in NBD mode instead of SAN. This issue only affects virtual machines that use hardware version 10 (vmx-10).

Workaround: Increase or decrease the size of the virtual drive (for example, to 2.01 TB, 3.99 TB).

DNVMWARE-1373 (27742)

When a virtual machine is cloned outside the vCenter Server, it may have the same UUID as the original virtual machine. If this cloned virtual machine is selected for a backup, the plug-in may back up the original virtual machine instead of the clone. To correct this issue, you must change the UUID of the cloned virtual machine. For more information about changing the UUID of a virtual machine, see

DNVMWARE-1443 (28921)

To back up virtual machines that are protected by VMware vSphere Fault Tolerance (vSphere FT) with plug-in version 11.2 or later, your environment must use VMware ESXi 6.0 build number 4192238 or later. If you use an ESXi host with an unsupported build, vSphere FT protection might become disabled during the snapshot process. This issue occurs because of an issue in earlier versions of the VMware ESXi host. This issue is more likely to occur when the virtual machine uses Windows 2008 or later as the guest OS and it uses the VMware Tools VSS provider to take quiesced snapshots. For more information, see VMware KB article 2145664.

DNVMWARE-1623, DNVMWARE-1671 (31423, 32123)

If you use VMware Virtual Volumes (VVols) with a storage array that does not support thick-provisioned disks by default, you might receive the following error message: Error creating disk Error creating VVol Object. This may be due to insufficient available space on the datastore or the datastore’s inability to support the selected provisioning type.

Workaround: To allow VVols to create thick-provisioned disks, enable thick provisioning on the storage array. For more information, see

DNVMWARE-1712 (32714)

CentOS and Red Hat Enterprise Linux (RHEL) 6.x:

If you are using either of these operating systems and versions and the Fallback Transport Mode is set to none, a VMware issue prevents the backup proxy from opening in HotAdd Transport Mode and causes it to open in network block device (NBD) mode instead.


System requirements

Operating systems

For a list of supported OS distributions and versions, see the VDDK 6.7 Release Notes.

NetVault Backup versions

The Plug‑in for VMware 12.0 requires NetVault Backup 11.4.5 or later.

For complete supported-platform information, see the Quest NetVault Backup Compatibility Guide available at

Upgrade and compatibility

Plug‑in for VMware 12.0 requires NetVault Backup 11.4.5 or later. For complete supported-platform information, see the Quest NetVault Backup Compatibility Guide.

Cannot browse mounted virtual machines after upgrading NetVault Backup: After installing the plug‑in, if you upgrade the NetVault Backup software, you must reinstall the plug-in on that machine. Otherwise, you cannot open the Drives node of a mounted virtual machine for any new file‑level backups.
Restart the NetVault Backup Service if “nvvmwmount.exe” was running during upgrade: If the mount process “nvvmwmount.exe” was running during an upgrade from 2.x, restart the NetVault Backup Service on the client.
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