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NetVault Plug-in for VMware 11.2 - User Guide

Introduction Installing the plug-in Configuring the plug-in Defining a backup strategy Using the image-level backup method Using the file-level backup method Restoring image-level backups Restoring file-level backups Troubleshooting

CBT-based image-level backup fails

An image-level backup for which CBT has been enabled reports an error and fails.

The job fails with the following error in the NetVault Backup logs:

Failed to get changed disk areas.

This issue occurs when a snapshot exists on a virtual machine when CBT is enabled. For snapshots that exist before enabling CBT, the changeId parameter is not set. So, when the QueryChangedDiskAreas API is invoked, it returns an error. For more information, see

To correct this problem, do either of the following:

Use the Reset Change Block Tracking option. This option reconfigures CBT on a virtual machine and allows you to run CBT-enabled backup that failed previously. For more information about this option, see Resetting CBT on a virtual machine.

SAN transport reports errors when multiple backups access the same datastore

A Linux®-based client may fail to read the contents of a virtual disk using the SAN transport mode if multiple backup processes are accessing the same datastore.

During a backup using the SAN transport mode, the following errors are reported:

San transport error: I/O Operation failed.

Error: One of the parameters supplied is invalid.

These errors are caused by a fault in the Linux kernel when handling SCSI reservation conflicts.

The errors are encountered on the following systems:

Red Hat® Enterprise Linux® (RHEL) 6.1 and earlier versions
SUSE® Linux Enterprise Server (SLES®) 11.1 and earlier versions

To correct this issue, upgrade to kernel version 2.6.32-220 or later on RHEL and kernel version 3.0.13 or later on SLES.

Default SCSI controller type on RHEL 7 and RHEL 6

When you create a virtual machine with RHEL 7 or RHEL 6 as the Guest OS, the SCSI controller type is set to VMware Paravirtual by default. The HotAdd transport mode does not work if either the backup proxy or the backup target uses Paravirtual SCSI controller.


To use HotAdd transport mode, set the SCSI controller type to LSI Logic Parallel or LSI Logic SAS when you create the virtual machine. For more information about configuring this setting, see the relevant VMware documentation.

Dell does not recommend changing the SCSI controller type for an existing virtual machine without testing to ensure that it operates normally with the new controller type.

File-level backups do not back up data for a reparse point

The file-level backup method does not back up data through a reparse point.

When a disk mounted as a reparse point on a Guest OS is included in a file-level backup, the backup completes without any errors or warnings. However, the plug-in does not back up any data for a reparse point. It is listed as an empty node on the Create Selection Set page.

The VMware API does not support this type of backup.


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