CommVault Interview Questions

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1. What is CommVault?

Ans: CommVault is a data protection and information management platform. It helps organizations access, protect and use all of their data to its true value. It is also used for taking data backups and recovery. CommVault is headquartered in Tinton Falls, New Jersey.

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2. What do you mean by the CommVault tool?

Ans: CommVault is an information and management solution that offers to protect and manage your business data. CommVault is a publically traded software company founded in the year 1988, located in the United States of America. This software can be used for data backup, recovery, and cloud management. CommVault, which is formerly known as Simpana, Software enables us to access and use of their data, anywhere and anytime, turning the data into a powerful strategic asset. This software solution also optimizes the data protection for the broad NetApp storage portfolio and many organize uses the CommVault as a backup server for the data recovery purpose.

3. What are the ways of achieving high availability?

Ans: There are three ways of achieving high availability in CommVault,

  • Log Shipping
  • SQL Mirroring
  • Clustering at the level of SQL

4. What are the features of the CommVault software tool?

Ans: The following are the key features of CommVault;

  •       Offers efficient storage management with the help of duplication for disk and tape.
  •       Provides simplified management via a single console system.
  •       Provides complete data protection and security.
  •       Users can use third-party screen readers with the help of command-line interfaces, web console, and admin console managements.
  •       Snapshot management and edge endpoint solutions
  •       CommCell management, data management, and media management are also possible.

5. What are the other ways of doing high availability?

Ans: There are various ways of performing high availability in CommVault;

  •       Log shipping
  •       SQL mirroring
  •       Clustering SQL level

6. Explain the types of copies in CommVault

Ans: We will have the data as one primary copy to which there will be secondary copies. We can create three types of secondary copies,

  • Synchronous secondary copy - includes data from a source copy
  • Selective secondary copy - includes valid full or synthetic full backup data
  • IntelliSnap backup copy - manages the control of snapshots which are started by a backup job. Contains archived index data

7. What are the copies and what are they?

Ans: In CommVault, we can see only one Primary copy and different auxiliary/secondary copies such as;

  •       Selective copy: this type of copy allows users to copy the specific backup system tools from different source copy. This source copy can be either a primary        or a synchronous copy.
  •       Inline copy: in this type of Copy, we can perform both primary and secondary copy tasks that are written to storage the backup phase itself.
  •       Synchronous copy: In Synchronous copy, all the primary data can be copied.

8. Explain about Global Dedup Storage Policy?

Ans: The global deduplication policy furnishes a common deduplication database(DDB) that can be shared by various storage policy copies. It allows the deduplication of data from multiple copies which results in removing redundant data.

9. Explain briefly about storage policy?

Ans: A storage policy in CommVault is a data management entity that contains a set of rules that will be applied in lifecycle management. This supports data protection in the sub client’s contents. Storage policy also associates with the client backup to storage tape or disks and here the policy will be used to set the data retentions.

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10. What are CommServe DR procedures?

Ans: CommServe DR is hardware fresh which consists of Copy DR sets this provides CommServe facilities and restores the CS DR procedures.

11. What is the global Dedup security policy?

Ans: This global duplication policy enables the data duplication across the multiple storage sets of disk libraries and database servers (DDB).

12. What is DDB in CommVault?

Ans: The following factors will give a brief explanation of DDB:

  •       DDB is an efficient way to transmit and data storage which is possible through detecting and eliminating duplicate data blocks.
  •       Duplication Database (DDB) system is protected by DDB backup sub-client methods
  •       When you create the storage policy with the help of duplication data, DDB backup will be created automatically under the file management system agent            on  the media client.

13. Tell me about the infrastructure that you worked on previously

Ans: This question will be mostly asked to a CommVault experienced candidate. The answer should include the number of Prod CommServe, DR CommServe, Media Agents, etc. Mention about all the backup servers that you have used.

14. How can we access reports in CommVault?

Ans: To get access to reports, go to the web console by hitting the URL in a browser. Log into your account and click on 'Reports'. In the case of a private metrics reporting server, you will be able to view the reports in the CommCell console.

15. Explain about Intellisnap?

Ans: Intellisnap backup is used to create a point-in-time snapshot of the data. It is mainly used for taking backup of live data and then continuing the live operations.

16. Explain about IRM

Ans: IntelliSnap recovery manager (IRM) is used to execute hardware storage systems snapshots into a recovery process with no effect on the production server. It also provides a centralized configuration wizard through which we can configure storage media, policies, etc. 

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17. Explain the steps involved in creating the CommVault proxy?

Ans: The below steps explains the steps involved in creating the CommVault proxy;

Step 1: Right-click on the client computer -> from the CommVault browser -> select the properties

Step 2: go to the properties dialog box -> click on the network button -> select the configuration firewall settings -> select checkbox

Step 3: Now click on the options tab -> choose the “computer is in DMZ and this will work as a proxy checkbox.

Step 4: Click on the incoming connection option -> now select the add

Step 5: select the Commserve_client_name from the list

Step 6: from the list -> select the Restricted -> click OK.

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18. What is the process that happens in backup copy operations in the proxy server?


  • The snapshot will be mounted to the ESX server
  • Once the snapshot is mounted, it will be treated as a file system, so the required contents can be read
  • The primary copy will be used to perform the file system backup
  • After the backup job is done, the snapshot will be unmounted

19. What are the types of backups available in CommVault

Ans: Commvault provides efficient backup and restores functionalities for any enterprise. These are the types of backups available in CommVault,

  • Full Backup
  • Incremental Backup
  • Differential Backup
  • Synthetic Full Backup
  • Selective Online Full Backup
  • Block-Level Backup

20. What are the main components of the CommCell environment?

Ans: There are 3 building blocks of the CommCell environment;

  • CommServe: This is the central management component that executes all the CommCell data operations.
  • Media Agent: this is a data transmission manager system that enables high-level data movement performance and handles the data storage packages.
  • Client: A client is a logical group of data agents that perform tasks like data protection, management, and movement of data association.

21. What is Intelisnap?

Ans: This Intelisnap takes the snapshot and then resumes many live operations. Intelisnap works in conjunction with storage arrays to offer snapshot functionalities for backup.

22. What are the uses of the proxy server?

Ans: The benefits of a proxy server such as;

  • Proxy server is used to access the storage array which is used to create a snapshot.
  • The snapshot is built on the ESX server designated for the snap mount.
  • This helps to unmount the snapshots
  • The mounted snapshot is treated as a file system and the required content will be read.
  • The file backup acts as a primary copy of the storage policy
  • When the backup task is finished, the snapshot is unmounted.

23. How can we use a specific set of tapes for a server backup?

Ans: We have to create a new scratch pool and add the media to it. Attach a subclient to the scratch pool. This can be done at two levels,

  • Storage policy level
  • Copy policy level

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24. What are the unit options of the CommVault area?

Ans: This enhances productivity with synchronization file security

  •       Reduces the risk, minimizes the information outpouring, improves the information handling capacity, and meet the compliance necessities.
  •       Simplifies the administration with one strong method for desktops, portable computers, and server information.
  •       Lower the value of data protection remote and mobile information
  •       Access the protected information from anywhere, anytime

25. What are the common/regular backup failures?

Ans: Here are some important common/regular backup failures;

  • Network communication issues
  • Client services may shut down during the time of maintenance
  • Media agent offline
  • When the destination disk library becomes full
  • Data path offline
  • VSS snapshot backup failure occurs

26. Explain about Silo in CommVault

Ans: A set of disk volume folders associated with DDB and contains deduplication data is called a Silo. This is used to eliminate data restore from tape to disk library. 

27. What are the entities that get backed up with VMWare backups?

Ans: We can perform backup on VMWare from a subclient. The entities that get backed up are,

  • Windows and Linux virtual machines 
  • VM templates
  • VMDK files
  • Virtual RDMs
  • GPT or dynamic disk volumes
  • vSphere tags
  • Fault-tolerant VMs

28. What are the types of transport modes available for VMWare backup?

Ans: The data of a Virtual Machine can be accessed by a VMware Backup Host using four methods,

  • SAN - VMware Backup Host should reside on a physical machine and be able to access Fibre Channel or iSCSI SAN
  • LAN - the data from storage will be read by ESX/ESXi host and sent to the VMware Backup Host through a network
  • HotAdd - if the VMware Backup Host is on a VM, we can use HotAdd to attach the VMDKs of the Virtual Machine that is being backed up to the VMware Backup Host
  • NBDSSL - this works similarly to LAN. In addition to LAN, NBDSSL uses SSL encryption for all the data that is passed through TCP/IP connection

29. Explain the difference between a clone and a snapshot


  • A clone is like a duplicate of the database. It contains the exact copy of data as that of the database
  • A snapshot is a copy of a database at a particular timestamp. We should take a subsequent snapshot if there are any changes made to the database. When we want to restore data, we will have a restore point to get the data from a certain point in time

30. What are CommVault Appliances?

Ans: Commvault HyperScale Appliance provides seamless scale and data protection solutions. It is mainly used for scaling out infrastructure with cloud-like economics. It is a storage architecture that provides a platform for indexing, storage, data security, automation, reporting, etc.

31. Explain the ways to restore data using CommServe?

Ans: There are two possible ways available to restore the data using CommServe;

  • Here user can directly restore the backup data from a DR export file location
  • By retrieving the data that is present in the disk or tape backup and then restore the DR data.

32. What is the process of moving DDB to a new media agent?

Ans: The following steps explain the process;

Step 1: Go to -> Deduplication engines -> under the storage resources

Step 2: now choose the DDP that you want to move -> then right-click on it -> click on move partitions

Step 3: Now choose the new Media agent option that is available in the target media agent.

33. What is DDB seeding?

Ans: DDB seeding is the predefined workflow that helps the user to transfer the data. These data are available in baseline backup and acts as a connection between the two sites with the help of removable disk drives such as USB data-driven devices. We can use DD seeding to start the workflow manually from the CommCell console component.

34. What is the default block size for duplication?

Ans: The default block size for the data duplication is 128kb.

35. What is synthetic full, full back up, and dash full?


Synthetic full: Synthetic full backup consolidates all the data incremental backups and appends the last backup data. Here the server (server is nothing but client machine or network utilization) performs very low utilization when compared to Full back up.

Full Backup: this full backup performs full utilization operation which is taken from the server.

Dash Full: this dash full performs operations like copying the unique blocks of the de-duplicate data, updates the DDB data, and also index the backup data.

36. What is SILO?

Ans: A silo is the collection of disk volume data folders that are associated with the DDB (De-Duplicate database). It contains the deduplicated data that is pre-written on the disk storage.

37. How does a CommVault works?


  • CommVault software tools contain the advanced modules which are used for data protection, analyzing the duplicate data, and search the data. All these advanced modules share the same set of back-end services and also offer advanced capabilities to interact with each other
  • Here data will be protected by installing CommVault agent software on the physical or virtual hosts that use the application native APIs or operating systems to protect all the data in a consistent data. This operation is controlled by a centralized server called CommServer.

38. What is the difference between a snapshot and a clone?

Ans: Cloning is used to make a copy of something whereas a snapshot makes an initial copy and then adds subsequent changes to it. Both snapshots and clones are considered a good approach to disaster recovery.

39. Is CommVault enterprise-level software?

Ans: The answer is yes, it is enterprise-level software. Using this CommVault software we can build the data modules from scratch and this software can be used independently based on one’s requirement.

40. How to perform a VMware backup?

Ans: The below-mentioned steps will help you perform a VM ware backup:

  • First navigate to the client computers -> from the CommCell console -> then select the virtualization- client->virtual server -> VMware -> backup-set.
  • Now right click on a sub-client -> click on the backup option -> here you need to select any one backup type such as full, incremental, or differential backups.
  • If you want to modify the backup -> go to default modify settings -> then click on the advanced.
  • If you want to run any program immediately-> click on immediate -> click configure -> specify the task -> click ok.
  • Click on home -> job controller -> then track the progress of the job.

41. Name the various types of backups available in CommVault?

Ans: The following are the different backups available in CommVault;

  •       Full backup
  •       Incremental backup
  •       Differential back up
  •       Synthetic full back up
  •       Block level back up

42. Name the different types of transfer modes available for CommVault?

Ans: The different types of transfer modes are such as;

  • Transport mode SAN (storage area network)
  • Data can be accessed directly when they are located in VMware host or we can call it as LUN.
  • Hot add transfer mode
  • Local area network (NBD and NBDSSL) transfer mode

43. List all day-to-day activities of a backup admin?

Ans: The following are the operations performed by the users;

  • User needs to check the available free space regularly and also mention the remaining space available in the disk libraries.
  • Extract the backup report which is already failed and analyze the issue. All you need to do is the rectification the process.
  • Check regularly for deployment, decommissions, and restores the requests.
  • You need to check for the media agent when they are not in offline mode.

44. How to access reports in CommVault?

Ans: Here users can access the reports through the cloud services portal and web console.

45. How you configure a cluster backup?

Ans: The steps are as follows;

  1. Create the cluster group -> add the client machines -> perform sync.
  2. For the windows software (Commvault) installation -> you need to prompt the passive node.
  3. Then perform installation -> schedule backup.

46. What is the HASH algorithm?

Ans: A HASH algorithm in CommVault is used in the duplication process whenever the system reads the block of data from multiple sources and also helps to generate a unique signature.

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John is a Post Graduate in Computer Science from Andhra University .She is currently working as an IT developer at hkr And he has great experience includes both IT development and operational roles. Connect with him on LinkedIn and Twitter. Thank you

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