Top Netbackup Interview Questions and Answers You Need to Know

Preparing for a Netbackup interview can be a daunting task, especially if you’re new to the field. However, with the right preparation and knowledge, you can ace your interview and land your dream job. In this article, we’ll cover some of the most frequently asked Netbackup interview questions and provide comprehensive answers to help you stand out from the competition.

Understanding Netbackup

Before we dive into the questions, let’s briefly discuss Netbackup. Netbackup is a powerful backup and recovery solution developed by Veritas (now Symantec). It is designed to protect mission-critical data across various platforms, including Windows, UNIX, and Linux operating systems. Netbackup provides a centralized management console for backing up and restoring data, as well as advanced features like deduplication, replication, and disaster recovery.

Netbackup Interview Questions and Answers

1. What is the difference between a User Backup, User Archive, and how do you take them?

   • A User Backup is a backup initiated by a user for their own data, typically residing in their home directory or other user-specific locations.
   • A User Archive is similar to a User Backup but is intended for long-term storage or archiving purposes.
   • To take a User Backup or User Archive, you can use the bpbackup or bparchive commands, respectively, from the command line or initiate them through the Netbackup client interface.

2. Explain the difference between Netbackup 5.x and 6.x versions.

   The main differences between Netbackup 5.x and 6.x versions include:

   • Netbackup 6.x introduced a new catalog format (known as the Relational Database or RBAK) for improved performance and scalability.
   • Netbackup 6.x supports advanced disk-based backup and recovery features, such as disk staging and disk pool management.
   • Netbackup 6.x includes support for VMware and Hyper-V virtualization platforms.
   • Netbackup 6.x introduced the Symantec Product Authentication Service (AT) for enhanced security.

3. In which location (path) are the temporary files located in Netbackup for Windows/Unix?

   • On Windows: C:Program FilesVeritasNetBackuptemp
   • On Unix/Linux: /usr/openv/netbackup/temp

4. How do you configure a client for automatic backups?

   To configure a client for automatic backups, follow these steps:

   1. On the Netbackup master server, create a policy and add the client to the policy.
   2. Define the backup schedule and other policy settings.
   3. On the client, ensure that the Netbackup client software is installed and configured to communicate with the master server.
   4. Verify that the client is included in the appropriate policy and that the backup schedule is running correctly.

5. What’s the difference between differential incremental and cumulative incremental backups? What happens when you mix them on Windows and Unix clients?

   • A differential incremental backup backs up all files that have changed since the last full backup.
   • A cumulative incremental backup backs up all files that have changed since the last full backup or the most recent cumulative incremental backup.
   • Mixing differential and cumulative incremental backups on the same client is not recommended, as it can lead to inconsistent backup sets and potential data loss.

6. How is a changed file determined on Unix?

   On Unix systems, Netbackup determines if a file has changed by comparing the file’s modification time and size to the corresponding information in the Netbackup catalog. If either the modification time or size differs, the file is considered changed and will be backed up.

7. When would you, or would you not, use cross-mount points?

   Cross-mount points allow Netbackup to cross mount point boundaries during backups and restores. You would use cross-mount points when you need to back up or restore data that spans multiple file systems or mount points. However, you may choose not to use cross-mount points if you want to restrict backups or restores to specific file systems or mount points for better control or performance.

8. What is the difference between a Volume Group and a Volume Pool?

   • A Volume Group is a logical grouping of volumes (tapes or disk pools) based on their physical location, such as a specific robot or disk pool.
   • A Volume Pool is a logical grouping of volumes (tapes or disk pools) used for a specific application or purpose, such as backing up Oracle databases or Windows clients.

9. How do you back up the Netbackup catalog, and why is it important? What do you have to do if you don’t have a catalog backup?

   • To back up the Netbackup catalog, you need to configure and run a catalog backup policy.
   • Backing up the catalog is crucial because it contains metadata about all the backup images, allowing you to restore data from those images.
   • If you don’t have a catalog backup, you will need to perform a time-consuming catalog recovery process, which may involve importing backup images from tapes or disk storage units.

10. How do you recover the Netbackup catalog?

    The process of recovering the Netbackup catalog depends on whether you have a recent catalog backup or not:

    • If you have a recent catalog backup, you can restore the catalog from the backup.
    • If you don’t have a catalog backup, you need to follow a multi-step process:
      1. Reinstall the Netbackup software on the master server.
      2. Import backup images from the available media (tapes or disk storage units).
      3. Rebuild the catalog database from the imported images.

11. How do you configure retention levels for backups?

    You can configure retention levels for backups by adjusting the retention settings in the backup policy. Netbackup provides several retention options, including:

    • Maximum number of full backups to retain
    • Maximum number of incremental or differential backups to retain
    • Retention period (in days, weeks, or years)

12. If you install the Netbackup Admin client on a Windows workstation, what else has to be done for it to work as an authorized server?

    To use the Netbackup Admin client on a Windows workstation as an authorized server, you need to perform the following steps:

    1. On the Netbackup master server, add the Windows workstation’s hostname or IP address to the “Servers” list in the Netbackup Administration Console.
    2. On the Windows workstation, install the Netbackup Remote Administration Console.
    3. Configure the Remote Administration Console to communicate with the Netbackup master server.

13. What is multiplexing? What are multiple data streams? Are they the same?

    • Multiplexing is the process of sending concurrent, multiple backups from one or more clients to a single storage device (tape or disk) and interleaving those images onto the media.
    • Multiple data streams refer to the ability of Netbackup to split a single backup image into multiple data streams, allowing for faster backups by utilizing multiple drive paths or threads.
    • While related, multiplexing and multiple data streams are not the same. Multiplexing combines multiple backup images onto a single storage device, while multiple data streams split a single backup image into multiple streams for improved performance.

14. How can you recover a corrupted backup image?

    If a backup image is corrupted, you can try the following steps to recover the data:

    1. Use the bpimmedia command to list the images on the tape or disk storage unit.
    2. Identify the corrupted image and its backup ID.
    3. Use the bpimport command with the -id option to import the corrupted image to a different location or storage unit.
    4. If the import is successful, you can attempt to restore the data from the imported image.

15. How can you assign barcode rules?

    To assign barcode rules in Netbackup, follow these steps:

    1. In the Netbackup Administration Console, go to “Media and Device Management” > “Media” > “Barcode Rules.”
    2. Click “Add” to create a new barcode rule.
    3. Specify the barcode pattern (using wildcard characters if needed) and the associated volume pool or scratch pool.
    4. Configure any additional options, such as media type or description.
    5. Save the barcode rule.

16. What are OTM and TIR?

    • OTM (Original Tape Manufacturer) is a Netbackup feature that allows you to specify the manufacturer of tapes that you want to use for backups. This helps ensure compatibility and reliability by only using tapes from approved vendors.
    • TIR (Tape Information Report) is a utility in Netbackup that provides information about tapes, including their type, density, and usage statistics.

17. What format does Netbackup write data to tapes?

    Netbackup writes data to tapes in the GNU tar format. However, the tar binary used by Netbackup has been modified from the original GNU source code.

18. How does Netbackup tie in with Media Manager?

    Netbackup and Media Manager (formerly known as Veritas Volume Manager or VxVM) work together to manage storage devices and media. Specifically:

    • Netbackup handles backup and restore operations, including scheduling, cataloging, and data movement.
    • Media Manager manages the physical storage devices, such as tape libraries and disk pools, and provides a layer of abstraction between Netbackup and the actual storage hardware.

19. How do you create a Storage Unit that will only be used by one client?

    To create a Storage Unit that will only be used by one client, follow these steps:

    1. In the Netbackup Administration Console, go to “Media and Device Management” > “Devices” > “Storage Units.”
    2. Click “Add” to create a new Storage Unit.
    3. Select the appropriate storage device types (e.g., disk or tape).
    4. In the “Storage Unit Properties” dialog, select the “Restrict” option under “Storage Unit Preferences.”
    5. Add the specific client that should be allowed to use this Storage Unit.
    6. Save the Storage Unit configuration.

20. What is the difference between the expiration date for a volume in Netbackup’s media catalog and Media Manager’s volume database?

    • In Netbackup’s media catalog, the volume expiration date is the date and time when the physical media (tape or disk) is considered no longer usable, based on the retention settings and policies.
    • In Media Manager’s volume database, the volume expiration date is the date and time when the volume is eligible for reuse or recycling, based on the media type and usage rules.

21. What is the difference between a frozen volume and a suspended volume?

    • A frozen volume is a volume that has been temporarily prevented from being overwritten or recycled, typically for administrative or troubleshooting purposes.
    • A suspended volume is a volume that has been temporarily suspended from being used for backups or restores, usually due to hardware errors or other issues with the volume.

22. How many Robot Control Hosts can a DLT tape library have?

    A DLT (Digital Linear Tape) tape library can have only one Robot Control Host, which is the server responsible for managing and controlling the tape library.

23. What do the following processes do: bpbkar, bpsched, bpbrm, bpdbm, ltid, AVRD?

    • bpbkar: The Netbackup client process responsible for performing backups and restores.
    • bpsched: The Netbackup scheduler process that manages and schedules backup jobs.
    • bpbrm: The Netbackup Resource Manager process that manages resources (storage units, drives, etc.) for backup and restore operations.
    • bpdbm: The Netbackup Database Manager process that manages the Netbackup catalogs and databases.
    • ltid: The Netbackup Device Manager process that manages and controls tape libraries and drives.
    • AVRD: The Automatic Volume Recognition Daemon that monitors tape drives and automatically assigns media to them.

24. Why is the Netbackup catalog considered the most important component?

    The Netbackup catalog is considered the most important component because it contains metadata about all the backup images, including the backup contents, locations, policies, and schedules. Without the catalog, it would be impossible to locate and restore backed-up data, making the catalog essential for the entire Netbackup environment.

25. What does status code 59 mean in the Netbackup Activity Monitor?

    Status code 59 in the Netbackup Activity Monitor indicates that a backup or restore job has failed due to a media error. This could be caused by issues with the tape drive, tape media, or related hardware components.

26. What are the installation processes for Netbackup 5.x and 6.x?

    The installation processes for Netbackup 5.x and 6.x are similar but have some differences:

    • Netbackup 5.x uses a traditional installation wizard or script-based installation.
    • Netbackup 6.x introduced the Netbackup Product Installation Wizard, which simplifies the installation process by automatically detecting and configuring components.
    • Netbackup 6.x also introduced the concept of deployment levels (Master Server, Media Server, and Client), allowing for more flexible installation options.

27. What is AVR mode?

    AVR (Automatic Volume Recognition) mode is a feature in Netbackup that allows tape drives to automatically detect and load the appropriate tape media for backup or restore operations. When a drive is in AVR mode, it can recognize and use any compatible tape that is loaded into it, without the need for manual intervention.

28. Why is a binary catalog more efficient than an ASCII catalog?

    A binary catalog is more efficient than an ASCII catalog for several reasons:

    • Binary data takes up less storage space than ASCII text, resulting in smaller catalog file sizes.
    • Binary data can be read and processed more quickly by the Netbackup processes, improving performance.
    • Binary data is less prone to corruption or human-readable errors compared to ASCII text files.

29. What are the main Netbackup daemons, and what are their roles?

    Some of the main Netbackup daemons and their roles include:

    • bprd: The Netbackup Request Daemon that handles client requests and starts other processes as needed.
    • bpbrm: The Netbackup Resource Manager that manages storage units, drives, and other resources.
    • bpdbm: The Netbackup Database Manager that manages the Netbackup catalogs and databases.
    • bpcd: The Netbackup Client Daemon that handles backup and restore operations on clients.
    • nbvault: The Netbackup Vault Manager that manages and coordinates vault operations.
    • nbemm: The Netbackup Enterprise Media Manager that manages media and devices.

30. How do incremental backups determine which files have changed?

    Incremental backups in Netbackup determine which files have changed by comparing the file’s modification time and size to the corresponding information stored in the Netbackup catalog. If either the modification time or size differs from the catalog data, the file