NetVault Plug-in for VMware 10.0.5

File-level backups

This file-level backup method is only available to Windows-based virtual machines. File-level backups allow you to restore a single file or a set of files. You can use these backups to recover from data loss due to user errors, data corruption, or accidental deletion of files.


	NOTE: Only the Windows version of the Plug‑in for VMware supports file-level backups of virtual machines.

The Plug‑in for VMware uses NetVault Backup Plug-in for FileSystem (Plug-in for FileSystem) for file-level backups.

File-level backup types

The Plug‑in for VMware supports the following types of file-level backups:

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Full Backup: A Full Backup provides a backup of all selected files and folders. Full Backups take longer to complete and consume more backup media. However, restores are faster since the plug-in is only required to restore a single saveset. Full Backups serve as the base backups for subsequent Incremental and Differential Backups

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Differential Backup: A Differential Backup provides a backup of files that are new or have changed since the last Full Backup. Differential Backups speed up recovery since the plug-in is only required to restore two savesets. However, these backups consume more storage space and take more time to complete than the Incremental Backups. Differential Backups duplicate the data backed up by previous backups of the same type.

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Incremental Backup: An Incremental Backup provides a backup of files that are new or have changed since the last Full or Incremental Backup. Incremental Backups consume minimum storage space and are quicker to perform. However, data recovery can take more time depending on the number of savesets that the plug-in is required to restore.

Defining a backup and recovery strategy

A well-designed backup strategy helps you to recover from the damages caused by failure and resume normal operations as quickly as possible. Before you start backing up your data, ensure that a good strategy is in place that safeguards your data against various failure modes, such as media failure, data corruption, user error, and complete loss of a data center.

Typically, your backup plan should define what backup methods are used, when and at what intervals the backups are performed, how the backups are stored, how long the backups are retained, and how the backup media are re-used.

The following are some example backup sequences to offer you guidelines:

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Full Backups only: You can choose to perform only Full Backups if the backup size is small, backup window is not an issue, or storage media is not a constraint. In such scenarios, you can schedule Full Backups every night or every N hours depending on the frequency of updates.

If a failure occurs, the plug-in is only required to restore a single saveset.

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Full and Incremental Backups: For quicker backups and minimum use of storage media, you can include Full and Incremental Backups in your strategy. For example, you can schedule Full Backups every Sunday and Incremental Backups every day or every N hours depending on the frequency of updates.

If a failure occurs, the plug-in is required to restore data from the recent Full Backup and each Incremental Backup in the backup sequence. The restore might take longer if several Incremental savesets have to be restored. For example, if the failure occurs on Saturday, the plug-in is required to restore the Full Backup taken on Sunday and Incremental Backups taken from Monday through Friday.

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Full and Differential Backups: For quicker restores and reduced media usage, you can include Full and Differential Backups in your strategy. For example, you can schedule Full Backups every Sunday and Differential Backups every day or every N hours depending on the frequency of updates.

If a failure occurs, the plug-in is required to restore data from the recent Full Backup and the last Differential Backup.

Using the image-level backup method

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Performing image-level backups

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Resetting CBT on a virtual machine

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Monitoring job progress

Performing image-level backups

To perform an image-level backup

In the Navigation pane, click Create Backup Job.

— or —

In the Navigation pane, click Guided Configuration, and then on the NetVault Configuration Wizard page, click Create Backup Jobs.

In Job Name, specify a name for the job.

Assign a descriptive name that allows you to easily identify the job for monitoring its progress or restoring data. The job name can contain alphanumeric and non-alphanumeric characters, but it cannot contain non-Latin characters. There is no length restriction. However, a maximum of 40 characters is recommended on all platforms.

In the Selections list, select an existing Backup Selection Set, or complete the following steps to create a set.

Click Create New to open the NetVault Backup Selections page.

Open the NetVault Backup Client on which the plug-in is installed, and then open VMware Plugin.

Open the applicable ESX/ESXi or vCenter Server. Depending on your VMware setup and inventory view type, open the applicable container nodes.


	NOTE: To switch between the two views, select the ESX/ESXi or vCenter Server, and in the Actions list, click Toggle Inventory View. This option is only available when server node is open.

Select the data that you want to back up.

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Back up all virtual machines within a container: Select the container node. Data selection is possible at all levels starting from the Datacenter node.

For example, to back up all virtual machines within a resource pool, select the corresponding resource pool node. Similarly, to back up all virtual machines hosted on an ESX or ESXi server, select the host node. In the VMs and Templates view, select the corresponding folder node.

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Back up individual virtual machines: Open the applicable container nodes (for example, Datacenter, Cluster, Resource Pool, and other nodes), and select the virtual machines that you want to back up. In the VMs and Templates view, open the folder node, and select the virtual machines that you want to back up.

Alternatively, select the container node, and then clear the check marks for the virtual machines that you do not want to back up.

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Back up individual virtual disks: Open the virtual machine node, and select the disks that you want to back up. Note the following:

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The virtual disks are named “Hard Disk 1,” “Hard Disk 2,” … “Hard Disk n.”

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The plug-in only lists those disks for which it can generate a snapshot.

Alternatively, select the container node (for example, Datacenter, Resource Pool, ESX Server, or folder) or the individual virtual machines, and specify the disk type (system or data) in the Backup Options Set. For more information about this setting, see Virtual machine disk selection options.


	NOTE: The virtual machine configuration files, “.nvram”, and log files are always backed up whether you select the entire virtual machine or its individual disks.

Click Save, and in the Create New Set dialog box, type a name for the set. Click Save to close the dialog box.


	NOTE: A set name can contain alphanumeric and non-alphanumeric characters, but it cannot include non- English characters. On Linux OS, the names can have a maximum of 200 characters. On Windows OS, there is no length restriction. However, a maximum of 40 characters is recommended on all platforms.

In the Plugin Options list, select an existing Backup Options Set, or complete the following steps to create a set.

Click Create New to open the VMware Plugin Backup Options page.


	IMPORTANT: On Windows, when you create a Backup Options Set for image‑level backups, you must use the default set “Default Backup Options — VMware Plugin — Windows” as the template. If you use any other set as the template, the backup may fail.

Under Backup Type, select one of the following options.

Table 1. Image-level backup types for virtual machines
Option	Description
Full	Select this option to back up all allocated sectors on a virtual disk.
Incremental	Select this option to back up disk sectors that have changed since the last Full, Differential, or Incremental Backup.
Differential	Select this option to back up disk sectors that have changed since the last Full Backup.

For more information about image-level backup types, see Image-level backups.

IMPORTANT: After reverting to a snapshot that is older than its last Incremental Backup, you must perform a Full Backup of that virtual machine before performing Incremental Backups again. If you perform an Incremental Backup, the following error occurs:

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vSphere 4.0: On vSphere 4.0, Incremental Backups include only those disk sectors that have changed since the last Incremental Backup instead of including all sectors that have changed since the virtual machine was reverted. This omission can result in data corruption or data loss without your knowledge as vSphere does not report this error. The jobs can succeed or fail, and in some cases succeed after multiple retries. Therefore, it is necessary to avoid this situation.

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vSphere 4.1 and later: On vSphere 4.1 and later, the job reports a filefault error and fails. For more information, see http://kb.vmware.com/kb/1021607.

Under VM disk selection options, select one of the following options.


	IMPORTANT: The disk selection option is applied to all virtual machines that you have selected explicitly by selecting the corresponding nodes or implicitly by selecting the container node (for example, ESX Server, Resource Pool, Datacenter, or folder). This option is not applied to virtual machines for which you have explicitly selected one or more virtual disks in the selections tree.

Table 2. Virtual machine disk selection options
Option	Description
Back up all disks	To back up all available virtual disks for the selected virtual machines, use this option. NOTE: The plug-in only backs up those disks for which it can generate a snapshot.
Exclude boot disk	To back up only the data disks and exclude the boot disks for the selected virtual machines, use this option.
Exclude data disks	To back up only the boot disk and exclude the data disks for the selected virtual machines, use this option. NOTE: To identify the boot disks, the plug-in only considers the active partitions on the MBR disk. Moreover, the plug-in only considers the first disk that meets the active boot partition criteria as the boot disk. The plug-in does not handle machines with multiple operating systems.

Under Other Options, configure the following settings.

Table 3. Other backup options for Plug‑in for VMware

Option

Description

Enable Changed Block Tracking for VM

By default, CBT is disabled for a virtual machine. If you want to perform Incremental or Differential Backups of virtual machines, you must enable CBT for the Full Backup that serves as the base backup for subsequent Incremental and Differential Backups.

To enable CBT on all virtual machines included in the backup job, select this check box. Before you select this check box, verify that the following requirements are met:

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The virtual machines are managed by ESX/ESXi 4.0 or later.

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The virtual machines use virtual hardware version 7 or later.

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The virtual machines do not use Physical compatibility RDM virtual disks, Virtual compatibility RDM (Independent Disks), or Virtual disks attached to a shared virtual SCSI bus.

If you select this check box and the plug-in fails to change this setting on a virtual machine, a warning message is logged.

If you do not select this check box, the plug-in does not change the CBT setting on the virtual machines during backups. Depending on whether CBT is enabled or disabled, the plug-in uses the appropriate backup method (CBT-based Full, Incremental, or Differential or non-CBT Full Backup) to back up the virtual machines.

NOTE: While this setting is applied to all virtual machines included in a backup job, the plug-in also provides you an option to enable CBT on individual virtual machines. For more information about enabling CBT on specific virtual machines, see Enabling CBT on a virtual machine.

Perform File Level Indexing

When you perform an image-level backup, the plug-in automatically generates file-level indexes for all supported volumes that are included in the backup snapshot. File-level indexing allows you to restore individual files and directories from Full, Incremental, and Differential image-level backups of virtual machines.

File-level indexing is available to volumes that use the following file systems:

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Windows: NTFS

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Linux and UNIX: EXT2, EXT3, and EXT4

The Plug‑in for VMware also supports volumes managed by Logical Volume Manager (LVM) on Linux-based systems and Logical Disk Manager (LDM) on Windows-based systems as single or spanned disks.

NOTE: The current version of the plug-in does not support Windows Server 2012 ReFS (Resilient File System) and Striped Disks.

File-level indexing does not affect the backup size. However, it increases the backup index size and the total backup time. The amount of time taken to perform file-level indexing depends on several factors, including the number of files, fragmentation of files on the volumes, network traffic, and load on the ESX or vCenter Server.

If you do not want to use image-level backups for file-level restores, clear this check box.

Enable Active Block Mapping

The Active Block Mapping (ABM) technology provides filters to remove unused blocks during backups, which reduce the backup size and the amount of data transferred over the network. You can use ABM with CBT to back up only active and changed blocks during Incremental and Differential Backups. Currently, ABM is only supported on the NTFS file system on basic disks.

ABM is disabled by default. Selecting this check box enables ABM, which allows the plug-in to back up only those sections of the virtual disks that are active. ABM scans the disk and detects inactive blocks; these blocks are then omitted during backups.

NOTE: ABM also removes deleted data. When you restore a virtual machine that was backed up using ABM, you cannot perform undelete operations for that virtual machine. Without Active Block Mapping, CBT includes the deleted blocks.

You can enable ABM for jobs that include both NTFS disks and non‑NTFS disks, but it is only applied to the NTFS disks.

Maximum Number of Parallel Streams

By default, the plug-in generates a single data stream for a backup job, and backs up the selected virtual machines in a sequential manner. To increase throughput and reduce overall backup time for image-level backups, you can configure the plug-in to perform parallel backups of multiple virtual machines.

This setting determines the maximum number of parallel data streams that can be generated for an image-level backup job. For example, if 10 virtual machines are included in a job, and you set this parameter to four, the plug-in tries to back up four virtual machines in parallel.

The actual number of parallel streams for a job depends on the following factors:

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The number of backup devices or streams available to the backup job. For example, if you set this parameter to 4 and only two tape drives are available or a NetVault SmartDisk can only support two concurrent streams, the plug-in only processes two virtual machines concurrently.

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The number of virtual machines included in the job. For example, if you set this parameter to 4, and the number of virtual machines selected for backup is 3, the plug-in creates only three data streams.

For parallel backups, the plug-in generates a parent process that coordinates the overall backup and individual child processes that perform the actual task of backing up the virtual machines. The maximum child processes that can be generated for a backup job is equal to the Maximum Number of Parallel Streams configured for the job. The parent and the child processes are all created on the NetVault Backup Client on which the plug-in is running.

When a child process acquires a backup device and creates a backup stream, it is assigned a task to back up a virtual machine. After the task completes, the process is assigned the next task if there are any more virtual machines to be backed up. Each task is assigned a Task ID. A snapshot is generated only when a virtual machine is assigned to a child process.

When configuring Maximum Number of Parallel Streams, consider the following:

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Verify that the value configured for this option does not exceed the number of backup devices or streams accessible to a job.

If the available devices are insufficient, more than one child process may try to access and write to the same device, causing significant increase in the overall backup time.

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The load of running multiple processes on a NetVault Backup Client can have a negative impact on performance.

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The load of backing up multiple virtual machines from the same datastore can increase the I/O activity on the datatsore.

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The load of backing up multiple virtual machine that are managed by the same ESX Server can increase the load on the host if you are using the LAN Transport mode (nbd/nbdssl) for data transfer.

NOTE: Only a single child process is used to back up the multiple disks of a virtual machine even if additional data streams are available. The child process creates a snapshot of the whole virtual machine and retains the snapshot until the job completes regardless of whether the whole virtual machine or its individual disks are backed up.

NOTE: This setting is not applied to backup jobs created with plug-in versions earlier than 2.5. For such jobs, the plug-in generates a single stream and backs up the virtual machines sequentially.

Click Save, and in the Create New Set dialog box, type a name for the set.

Select or create the Schedule Set, Target Set, and Advanced Options Set. For more information about these sets, see the Dell NetVault Backup Administrator’s Guide.

To submit the job for scheduling, click Save & Submit. You can monitor the job progress from the Job Status page and view the logs from the View Logs page.

To save the job definition without scheduling it, click Save. You can view, edit, or run this job from the Manage Job Definitions page. This job is not displayed on the Job Status page until you submit it.

For more information about Job Status, View Logs, and Manage Job Definitions, see the Dell NetVault Backup Administrator’s Guide.

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NetVault Plug-in for VMware 10.0.5 - User Guide

File-level backups

Defining a backup and recovery strategy

Using the image-level backup method

Performing image-level backups