If you are in search of Commvault interview questions, then you have landed at the right place. In this blog, we have collected the most frequently asked Commvault Interview Questions and Answers for both freshers and experienced, which will help you to ace the interview. The questions presented over here are curated based on the opinions of Commvault industry experts.

But before starting, let’s understand how the demand is continuously increasing for Commvault professionals worldwide:

  • Currently, Commvault has a market share of 9.81% - datanyze.com
  • Commvault professionals have huge opportunities across various domains and it is expected to rise even more in the near future.
  • On average, a Commvault Backup Administrator’s salary ranges around $94,952 per annum in the US - ZipRecruiter.com

Now, I hope you have got a clear idea of Commvault’s demand, career opportunities, and salary insights. To simplify your interview preparation process, we have segregated interview questions into:

In This Interview Questions, You Will Learn

Without wasting much time, let's discuss every topic in detail.

Commvault Interview Questions

Q1. What is Commvault?

Ans. Commvault is a data management platform that assists organizations with data backup and recovery, cloud, virtualization, disaster recovery, security, and compliance.

Commvault software consists of modules to backup, restore, archive, replicate, and search data.

Q2. What is Commvault Simpana?

Ans. Simpana is one of the features of Commvault’s enterprise backup software platform that is specially designed for backup, archive, and reporting data. Simpana is the new version of the Deduplication process introduced by Commvault.

Q3. What are the key features of Commvault?

Ans. The key features of Commvault are listed below:

  • Provides complete data protection and supports all the major applications, operating systems, databases, and mobile devices. 
  • Efficient storage management using deduplication for disk and tape.
  • Simplified management through a single console
  • Advanced security and encryption
  • We can use third-party screen readers with a command-line interface, web console, and admin console.
  • Snapshot Management
  • Edge Endpoint Solutions
  • CommCell Management
  • Media Management
  • Data Management

Q4. What are the various ways of doing High availability?

Ans. The various ways of doing High availability are listed below:

  • Log shipping
  • SQL mirroring
  • Clustering SQL level

Q5. Explain storage policy?

Ans. A storage policy is a data management entity with a set of rules that describe the lifecycle management of protected data in the Subclient’s content. It manages the Subclient’s data even when it stays on other servers in Commcell.

The set of rules includes how to manage data, protect data, where it will reside, and other management options such as compression, encryption, and deduplication of data in protected storage.

Below mentioned are the different types of storage policies:

  • Standard
  • Incremental
  • Disaster recovery backup

Q6. What are the types of copies that are available and explain them in detail?

Ans. We have only one primary copy and to that, we will be having different types of auxiliary/ secondary types of copies. The list of secondary copies available are as follows:

  • Selective Copy
  • Synchronous Copy
  • IntelliSnap backup Copy

Q7. What are the types of copies that are available and explain them in detail?

Ans. We have only one primary copy and to that, we will be having different types of auxiliary/ secondary types of copies. The list of secondary copies available are as follows:

Synchronous Copy, Selective Copy & IntelliSnap Backup Copy.

  • Synchronous Copy: Automatically includes all the valid data from a source copy.
  • Selective Copy: Automatically includes valid full or synthetic full backup data based on certain specifications. It also has a manual job selection option which lets you choose any type of job, including non-full backups.
  • IntelliSnap Backup Copy: Manages the retention of jobs that are created by a backup job. It also holds archived indexed data if the snapshot is granularly indexed.

Q8. What is DDB in Commvault?

Ans. 

    • Deduplication is an efficient way of transmitting and storing data through detecting and eliminating duplicate blocks of data while backups.
    • Deduplication DataBase (DDB) is protected by DDB Backup Subclient.
    • When a storage policy is created with deduplication enabled, DDB Backup Subclient is also created automatically under the file system agent on the media client agent where the DDBs are hosted.

Checkout Commvault Tutorial

Q9. How to configure Commvault Proxy?

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Ans. To configure the Commvault Proxy on the new client, follow the below steps:

  • Step1: Right-click on the client computer to be used as a Commvault proxy from the Commvault browser and select the properties. 
  • Step2: From the properties dialog box, click on the Network button and select the configure firewall settings checkbox.
  • Step3: Click on the options tab and choose “this computer is in DMZ and will work as a proxy checkbox.”
  • Step4: Click on the incoming connections tab and select add.
  • Step5: Select the CommServe_client_name from the list.
  • Step6: From the State list, select RESTRICTED and click OK.
  • Step7: From the State list, select RESTRICTED and click OK.

Q10. Explain Commcell environment.

Ans. A Commcell environment is the logical grouping of all the software components that secure, transfer, and manage data and information. It contains a CommServe host, MediaAgent, and Clients.

  • CommServe - It is the central management component that coordinates and executes all Commcell operations.
  • MediaAgent - It is a data transmission manager in the Commcell environment, which enables high-performance data movement and handles data storage libraries.
  • Client - A Client is a logical group of agents that defines the protection, management, and movement of data associated with the client.

Q11. How does Commvault work?

Ans. 

  • Commvault software contains modules for protecting, analyzing, replicating, and searching data; all these modules share the same set of back-end services and advanced capabilities to seamlessly interact with each other.
  • Data is protected by installing agent software on the physical or virtual hosts that use the application native APIs or operating systems to protect data in a  consistent state. This data is then backed up through Media Agent to the disk, tape, or cloud storage. The entire data management is controlled by a centralized server called CommServe.

Q12. What is Silo?

Ans. A Silo is a collection of disk volume folders that are associated with the Deduplication Database. It contains the deduplicated data that are written on the disk storage.

Q13. What is Hash Algorithm in Commvault?

Ans. A hash algorithm is used in the deduplication process in the Commvault whenever a block of data is read from the source and a unique signature is generated for the block of data using a hash algorithm.

Q14. What is the default block size for deduplicated storage policies?

Ans. The default block size for deduplicated storage policies is 128kb.

Q15. What percentage of the deduplication ratio that we could maintain so far?

Ans. This can be a generalized answer and the ratio that we could maintain is as follows:

  1. About 90% or more when it comes to filing systems backups
  2. Between 70% to 95% when it comes to the database backups

Q16. Where can you download the reports in Commvault?

Ans. You can download and view the reports in Commvault through the web console.

Q17. How to access reports in Commvault?

Ans. You can access reports through the cloud services portal and web console.

Q18. What is the main difference between a Snapshot and a Clone?

Ans. Cloning is nothing but making a copy of something while a snapshot makes an initial copy and then makes subsequent changes to it. Both cloning and snapshot are considered to be good approaches for disaster recovery.

Q19. What is IRM and how does it work?

Ans. IRM stands for the IntelliSnap Recovery Manager that performs hardware storage snapshots directly into a recovery/protection process for smaller environments. It offers fast and easy Snap backups, centralized configuration, application support, etc.

The following steps show how IRM works:

  •  Snapshot job initiates through a schedule or on-demand Intellisnap job from the Commcell console.
  • The array is accessed through a snapshot job when it is started to create a snapshot of the content.   
  • The snapshot is mounted for post-snap operations on the source computer.
  • The snapshot is unmounted.
  • Now snapshot provides high-speed mount/revert/restore operations.

Q20. What are the Deduplication Building Blocks?

Ans. Commvault software runs a building block approach for data management. A building block is a combination of server and storage to protect data sets regardless of the type or origin of the data.

Deduplication Building Blocks will allow you to protect huge amounts of data with minimal infrastructure, better scalability, and faster backups.

Q21. What is DDB seeding?

Ans. DDB seeding is a predefined workflow that allows transferring initial baseline backup among two sites using a removable disk drive.

Q22. What is ContinuousDataReplicator (CDR)?

Ans. ContinuousDataReplicator (CDR) replicates data from source to destination. It provides data protection and recovery support for all types of data including application data and file system.

Q23. Is commvault an enterprise level software?

Ans.

  • Yes, it is an enterprise-level software.
  • Using Commvault software is simple; it is built up from scratch and has different modules which can be used independently based on the need.

Commvault Backup Interview Questions

Q24. How does Commvault backup work?

Ans. Commvault presents the most efficient backup and restores data in enterprises from mainstream applications, operating systems, and databases. Commvault backup uses agents to interface with applications or files and facilitates the transfer of data from production systems to protected environments.

There are various types of backups available in Commvault:

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

Q25. What are the common/regular backup failures that one experiences most of the time?

Ans. Some of the common or more frequent backup issues reported are as follows:

  • Network communication issues
  • Client services might be shut down for maintenance
  • Media agent offline
  • Destination disk library full
  • Data path offline
  • VSS snapshot backup failure

Q26. How does the Backup Copy work for IntelliSnap Backup?

Ans. The backup copy operation allows you to copy snapshots of the data to any media. The primary snapshot stores the metadata information associated with the snap backups and when the backup copy operation is running, the primary snapshot data is copied to the media associated with the primary copy.

The backup copy can be configured in two ways:

  • Inline backup copy - Run during IntelliSnap backup job.
  • Offline backup copy - Run independently of the IntelliSnap backup job.

Q27. How to perform a VMware backup?

Ans. Performing a backup is like capturing data for all of the virtual machines in a subclient.

The below-mentioned steps will help you perform a VMware backup:

1. Navigate to client computers from the Commcell console and select Virtualization-client->virtual server->VMware->backup-set.

2. Now right click on a subclient and click backup.

Select the backup type: 

  • Full
  • Incremental
  • Differential
  • Synthetic Full                       

3. If you want to modify default modify settings or specify advanced options, then click Advanced.

4. To run a job immediately, click on Immediate or to create a backup schedule, then click configure to specify the schedule and click ok.

5. Click on Home->Job Controller to track the progress of the job.

Q28. What are the different types of transport modes available for VMware?

Ans. Transport modes are selected automatically for restore and backups based on the VSA proxy used and also when the virtual machines being backed up or restored.

The following are the different types of transport modes available in VMware:

  • SAN (Storage Area Network) - It supports directly connected storage through Internet SCSI or Fibre Channel protocols. 
  • HotAdd - In this, VSA is installed on the virtual machine residing on an ESX server.
  • Local Area Network (NBD and NBDSSL) - This transmits data over the TCP/IP connection between the proxy server and the ESX server.
  • NAS (Network Attached Storage) - This enables VSA proxy computer to read data directly from the network file server.

Q29. List out all the day-to-day activities of a backup admin.

Ans. First thing first, the backup admin will have to monitor whether all the scheduled jobs are running as per they are designated. If not, then they have to go through the jobs and understand the fault and rectify the same.

Further, they have to involve themselves with some of the following health checkups:

  • Have to check for Media agent so that they are not in offline mode
  • Have to make sure to regularly check the free space or the remaining space that is available in the disk libraries
  • Extract a backup report which is failed and analyze the same so that the rectification process can be continued.
  • Check regularly for deployment, decommissions, restores requests within the reporting tool.

Q30. Please explain the infrastructure that you have worked on previously.

Ans. This should be an honest reply back to the interviewer because this is a real-time question that can be answered based on the experience available.

Q31. What will happen in Backup copy operations in the proxy server?

Ans. During the backup copy operations, the following activities are executed:

    • The snapshot of the information is mounted to the ESX server which is solely designated for the snap mount.
    • Once the snap is mounted, then it is treated as a file system and the required contents are processed and read
    • The backup of the file system is performed to the Primary copy of the storage policy.
    • Once the backup copy job is finished, then the snapshot will be unmounted.

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