NetVault Plug-in for FileSystem 12.1


	NOTE: In a cluster environment, you may require the Disk Signature information during a System State restore if the shared cluster disks are changed after a backup. The Disk Signature information can be obtained using the Windows “dumpcfg.exe” utility. For more information about this tool, consult the relevant Windows documentation.

About multistream backups

The NetVault Backup Plug‑in for FileSystem can be configured to perform multistream operations when you are backing up large amounts of data. Multistream backups improve backup performance by using parallel streams to transfer data.

During multistream backups, the plug-in splits the Backup Selection Set is into smaller selection groups and uses separate child processes to perform parallel backups of these selection groups.

You can use the multistream options to do the following:

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Back up multiple volumes, network shares, and mount points simultaneously

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Back up a single volume using multiple parallel streams

You can specify the maximum number of parallel data streams that the plug-in can use for each job. The plug-in allows up to eight parallel streams.

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.

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Windows System State Backups: For System State backups on Windows, you can choose either of the following strategies:

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Back up only the System State data

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Back up the C Drive and System State data

Backing up the System State data with C drive has the following advantages:

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It eliminates duplication of the system files in a saveset. If you run two separate jobs, the system files are included in both savesets.

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You can use this backup to perform a disaster recovery.

The VSS method is recommended for a consistent backup of the System State data.

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Policy-based backups: At the enterprise-level, you can create a policy to back up the root directory on Linux and UNIX clients and all fixed drives and System State on Windows clients. For more information about backup policies, see the Quest NetVault Backup Administrator’s Guide.

Performing Full Backups

To perform Full Backups:

In the Navigation pane, click Create Backup Job to start the configuration wizard.

You can also start the wizard from the Guided Configuration link. In the Navigation pane, click Guided Configuration, and then on the NetVault Configuration Wizard page, click Create Backup Jobs.

In Job Name, type a name for the job. Assign a descriptive name that allows you to easily identify the job for monitoring its progress or restoring data.

A 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 machine, and then open File System.

Select the data that you want to back up:

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Back up entire system: On Linux and UNIX systems, select the root node (“/”).

On Windows, select the Fixed Drives node. To back up data on removable drives, select the Removable Drives node.

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Back up individual items: Open the parent node. Browse through the directory tree, and locate the items that you want to back up.

To include a file or a directory, select the corresponding check box. When you select a parent node, the child items are automatically included in the backup.

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Exclude child items: To exclude a file or directory within a selected parent node, click the corresponding check box to replace the check mark with a cross.

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 contain non‑Latin 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 File System Plugin Backup Options page.

Select the backup method and backup type.

Option

Description

Backup Method

Under Backup Method, select the applicable option:

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Standard: To perform native file system backups, select the option. On Linux- and UNIX-based systems, you can only use the Standard Backup method.

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Volume Shadow Copy Service (VSS): To perform VSS-based backups, select this option. This backup method is only available on Windows-based systems.

The plug-in uses a VSS provider to create snapshots, and uses these copies to perform backups to disk- or tape-based storage devices. You can also use the VSS backup method to create persistent snapshots on supported disk arrays.

For more information about backup methods, see About backup methods.

Backup Type

Under Backup Type, select the Full option.

For more information about backup types, see About backup types.

On Windows-based machines, configure the following snapshot options.

Table 1. Snapshot options

Option

Description

Backup Files to Storage

This option is selected by default.

To copy the selected data from snapshots to a storage device, leave this check box selected.

The plug-in uses a suitable VSS provider to create persistent or non persistent snapshot on the client, and copies the selected data from the snapshot to the storage device.

Retain Snapshot as Persistent

To retain persistent snapshots on disk arrays, select this check box.

Note the following:

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If both Backup Files to Storage and Retain Snapshot as Persistent check boxes are selected, the plug-in copies the selected files to a storage device, creates a snapshot on storage array, and adds the snapshot information to the backup index.

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If only the Retain Snapshot as Persistent check box is selected, the plug-in just writes the index entries to the storage device and creates a snapshot on storage array.

Discard After

The Discard After option can be used to delete persistent snapshots from Disk Array after a specified period. This option is only available when you use persistent snapshots to perform backups to a storage device and retain the snapshot as backup on the disk array (that is, the backup uses Retain Snapshot as Persistent option).

To configure snapshot expiration setting, select this check box. Type or select the period, and in the associated list, select the Day, Week, Month, or Year option.

Regardless of the saveset expiration setting, a snapshot is automatically deleted as per its retirement settings on disk array.

To expire a snapshot, login to Dell Compellent Storage array, and manually expire the snapshot.

Otherwise, it expires as per retention policy selected while creating a snapshot.

Perform Backup Off-Host using Client

This option allows you to off-host the backup on a remote client machine, where the backup is initiated by the off-host remote client.

The off-host remote client mounts the snapshot, writes file data to the backup stream, unmounts the snapshot, and returns the backup status to the primary client machine. After the backup is completed, the persistent snapshot is deleted.

This option is available only if Backup Files to Storage and Retain Snapshot as Persistent is selected.

Configure the following backup options.

Table 2. Backup options for Full Backup
Option	Description
Ignore truncated files	NOTE: This option is only supported on Windows-based machines and can be used with the FileSystem plug-in and Storage Manager. The Storage Manager allows running a truncation policy to move data blocks from the primary storage and free up disk space. The Storage Manager moves the files that meet the truncation criteria from the primary storage to archive tiers of storage, and sets the Windows offline attribute for these files. Depending on the truncation policy, the Storage Manager leaves a stub file on the disk when a file is truncated. If you select the Ignore truncated file(s) check box, the Plug‑in for FileSystem omits the offline files during Full, Incremental, and Differential Backups. If you do not select this check box, the Storage Manager retrieves the truncated files from the archive tiers when the plug-in tries to read the stub files. The deduplicated files are rehydrated during this process. The archived truncated files will not appear during restore.
Check For Files Being Modified During Backup	To mark the files that are being modified during a backup, leave this check box selected. During restore, these files are not restored by default. To restore these files, you must set the option Restore Files Modified During Backup on the Restore Options Set. If you do not want to check for files that are being updated during backup, clear this check box. The Check For Files Being Modified During Backup option is disabled for the VSS backup method.
Backup through Mount Points	This check box is only available on Windows. It is selected by default. If you do not want to back up the data on NTFS mount folders, clear this check box.
Backup through Remote Mounts	This check box is only available on Linux and UNIX. It is not selected by default. If you want to back up the data on mounted file systems, you must select this check box. NOTE: If you do not select this check box, the plug-in does not back up any remote mount points that are included in the Backup Selection Set. The plug-in excludes the remote mount points and does not provide any error or log messages in the Job Logs.
Check for and Skip Locked Mandatory Locking Files	To check whether mandatory locking is enabled on the system or not, select this check box. If mandatory locking is enabled, the plug-in tries to lock the file before backing it up. If the plug-in is unable to lock the file, it skips the file. (For example, if the file is locked by some other application, the plug-in cannot lock it for backup, and hence skips the file.) This check box is only available on Linux and UNIX systems.
Enable Restartable Backup	To add the ability to stop a job and resume it later from that point, select this check box. When you stop the job, the plug-in generates an index for all items that have been processed up to that point and writes the index to the backup media and NetVault Database. The job status is then set to Job Stopped. If the plug-in is writing a large backup index, the jobs status continues to be reported as “Writing to Media: Storing Backup Index” until the index is written. When you restart the job later, the plug-in runs an Incremental Backup job to back up the remaining files and folders. You can stop and resume a job from the Job Status page. For more information, see Stopping a job and Restarting a job.
Path to Backup Log	To generate a backup log file, type the filename. The log provides a list of files that are selected for the backup. The files that are backed up successfully are marked with an “o” and the others are marked with an “x.” You can use this option with an Incremental Backup to determine which new or changed files have been backed up. If you specify an existing filename, the plug-in overwrites the file. The log file is created in CSV file format (.csv), and includes details such as file size, date modified, and file type.

Configure the following options to perform multistream backups.

Option

Description

Utilise Multiple Streams During Backups

By default, the plug-in generates a single data stream for a backup job, and backs up the selected items in a sequential manner.

You can use this option to perform multistream backups. For more information, see “About multistream backups.”

When you select this check box, the plug-in splits the Backup Selection Set into multiple selection groups. It creates a selection group for each volume and network share included in the set and uses separate child processes to perform parallel backups of the selection groups.

You can also configure the plug-in to create separate selection groups for a single volume and use multiple streams to back up the data. For more information, see Use Heuristics for large Single Volume backups.

You can specify the maximum concurrent streams on a per-job basis. The Maximum Concurrent Streams setting determines the number of selection groups that are backed up simultaneously.

Maximum Concurrent Streams

The value configured for the Maximum Concurrent Streams option determines the number of child processes that are started concurrently on the client. For example, if there are six selection groups, and this option is set to 4, four child processes are started on the client. After acquiring the backup device and media, a child process generates a backup stream to back up the items within the selection group. When a child process completes its task, another child process is then started to back up the next selection group. This process continues until all selection groups are backed up.

If any child process is unable to acquire the backup device and media, it remains in a “waiting for media” state until the device and media become available. For example, if only two tape devices are available for four child processes, the processes that are able to acquire the device and media start backing up the data immediately, while the other processes remain in a waiting state until the device and media become available.

We recommend that you configure this option according to the capabilities of the client on which the job is running and the number of devices that are available to the job. The inability to acquire device and media can delay the job. In addition, running multiple concurrent processes on systems with a single processor can degrade the system performance.

By default, the plug-in uses two streams for backups that are configured as multistream jobs. The plug-in allows up to eight parallel streams.

Note the following:

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A single stream is used to back up all items in a selection group.

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If any child process fails to back up the items in a group, the entire job fails.

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If any child process reports any warnings, the entire job completes with warnings.

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Restores of multi-stream backups are performed sequentially.

NOTE: The Backup Options Sets (default and user-defined) created using a plug-in version prior to 11.0 do not include the multistream options. To apply multistream options to pre-existing jobs, edit the job and assign a set that includes these options.

Use Heuristics for large Single Volume backups

When backing up a large volume, you can configure the plug-in to dynamically split the data into multiple selection groups and use multiple parallel streams to back up these groups.

The criteria used to determine the selection groups include the following:

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Number of peer directories

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Number of sub-directories

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Number of files within a directory

After identifying the selection groups, the plug-in creates a child process to back up each selection group. Each child process uses the same criteria to identify parts of its backup that can benefit from a separate stream. If the current stream count has not exceeded the maximum allowed streams, the plug-in assigns a new child process to back up the sub-group. Otherwise, it uses the current stream to back up the sub-group.

During Incremental Backups, only the top-level selection groups use separate data streams; the child processes do not attempt to split the selection groups.

NOTE: This feature is intended for single volume selections that contain large amounts of data (for example, volumes that are larger than 1TB in size). It is not likely to benefit small backups and should not be used in those cases.

Always use a new stream when crossing a mount point

When you select this check box, the plug-in uses separate streams to back up the mount points that exist on the volumes.

You can use this option with the Use Heuristics for large Single Volume backups option.

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

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


	NOTE: When performing multi-stream backups, do not select the Ensure backup is the first on the target media check box. If you select this check box for multi-stream backups, each data stream targets a separate piece of media to exist as the first backup on the media item. Thus, if a backup generates five streams, the job tries to obtain five blank or new media items. This option does not apply to disk-based storage devices.

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 Quest NetVault Backup Administrator’s Guide.

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NetVault Plug-in for FileSystem 12.1 - User Guide

About System State Backups

About multistream backups

Backup and recovery strategy

Performing Full Backups