Commvault

Commvault

Top Interview Questions

About Commvault

 

Introduction to Commvault

Commvault is a leading provider of data protection, backup, recovery, and information management solutions for enterprises and organizations of all sizes. Founded in 1996 and headquartered in Tinton Falls, New Jersey, USA, Commvault has established itself as a pioneer in the field of data management, helping businesses protect their critical information assets in an increasingly complex digital landscape. Its solutions are designed to address the growing challenges of data explosion, regulatory compliance, cybersecurity threats, and cloud adoption.

The core mission of Commvault is to simplify and automate the process of managing data across on-premises, cloud, and hybrid environments. It enables organizations to maintain business continuity, safeguard sensitive information, and leverage data as a strategic asset.


Key Features of Commvault

Commvault provides a comprehensive suite of features for data protection and management. Some of the most notable features include:

  1. Data Backup and Recovery
    Commvault offers reliable and flexible backup solutions for a wide range of environments, including virtual machines, databases, applications, and endpoints. The platform supports both full and incremental backups, allowing businesses to minimize storage requirements while ensuring data integrity. Recovery can be performed at granular levels, such as files, folders, or entire systems, depending on the organization's needs.

  2. Cloud Integration
    Modern enterprises increasingly adopt cloud-based solutions, and Commvault provides seamless integration with public, private, and hybrid clouds. The platform supports major cloud providers like AWS, Microsoft Azure, and Google Cloud Platform. This allows businesses to securely back up, archive, and recover data from the cloud, enabling flexible disaster recovery and business continuity strategies.

  3. Deduplication and Storage Optimization
    Commvault incorporates data deduplication technology to eliminate redundant copies of data. This significantly reduces storage costs and optimizes bandwidth usage, especially during backup and replication processes. The solution supports both client-side and server-side deduplication, providing flexibility in managing storage resources efficiently.

  4. Snapshot Management
    The platform enables organizations to create snapshots of critical data and applications. Snapshots are point-in-time copies that allow for rapid recovery in case of data loss or corruption. This is particularly useful for virtualized environments, databases, and mission-critical applications where downtime can have serious business implications.

  5. Disaster Recovery
    Commvault’s disaster recovery capabilities ensure that organizations can quickly restore operations in the event of hardware failure, cyberattacks, or natural disasters. The solution supports automated failover and failback processes, reducing downtime and minimizing the impact on business operations.

  6. Endpoint Protection
    In today’s mobile and remote work environments, endpoint data protection is essential. Commvault allows organizations to back up laptops, desktops, mobile devices, and remote systems, ensuring that data remains secure regardless of location. It also offers the ability to manage endpoint data centrally, simplifying administrative tasks.

  7. Compliance and eDiscovery
    Many industries face strict regulatory requirements related to data retention and protection, such as GDPR, HIPAA, and SOX. Commvault provides robust compliance tools, including automated retention policies, legal holds, and eDiscovery features. These capabilities enable organizations to search, retain, and retrieve data efficiently for legal or regulatory purposes.

  8. Ransomware Protection
    Cybersecurity threats like ransomware can compromise critical business data. Commvault includes ransomware detection, prevention, and recovery capabilities. Its secure backup architecture and anomaly detection tools help organizations quickly respond to attacks and restore affected data without paying ransom demands.

  9. Analytics and Reporting
    Commvault offers powerful reporting and analytics tools to provide insights into backup performance, storage utilization, and compliance status. Organizations can generate dashboards and reports to monitor their data management operations and make informed decisions to optimize resources.


Architecture of Commvault

Commvault’s architecture is designed to be scalable, flexible, and suitable for enterprises of all sizes. The main components include:

  1. CommServe
    CommServe is the central management server that orchestrates all backup, recovery, and data management activities. It stores configuration information, maintains metadata about backups, and communicates with all other components in the Commvault environment.

  2. MediaAgent
    MediaAgents handle the actual movement of data between clients and storage targets. They manage backup data, replication, deduplication, and restores. By distributing workloads across multiple MediaAgents, organizations can achieve high performance and scalability.

  3. Clients
    Clients are the machines or applications whose data is being protected. Commvault supports a wide range of clients, including Windows, Linux, Unix servers, virtual machines, databases (Oracle, SQL Server, SAP, etc.), email systems (Exchange, Office 365), and cloud services.

  4. Storage Targets
    Commvault supports multiple storage types, including disk, tape, deduplicated storage, cloud storage, and object storage. This allows organizations to optimize storage based on cost, performance, and retention requirements.


Commvault Use Cases

  1. Enterprise Backup and Recovery
    Organizations can back up critical systems and applications, ensuring that data can be recovered quickly in case of accidental deletion, system crashes, or disasters.

  2. Cloud Migration
    Commvault helps organizations migrate data securely from on-premises environments to cloud platforms. Its cloud-native features simplify the migration process while maintaining compliance and security.

  3. Ransomware Recovery
    Businesses can use Commvault to protect against ransomware by creating immutable backups that cannot be altered by malicious actors.

  4. Regulatory Compliance
    Commvault helps enterprises meet regulatory and legal requirements through automated retention policies, legal holds, and secure archival solutions.

  5. DevOps and Test Environments
    Organizations can leverage Commvault to create copies of production data for testing, development, or analytics purposes without impacting live systems.


Advantages of Using Commvault

  • Comprehensive Data Protection: Covers physical, virtual, cloud, and endpoint environments.

  • Scalability: Can handle small setups to large enterprise environments with multiple data sources.

  • Efficiency: Deduplication and storage optimization reduce costs.

  • Regulatory Compliance: Provides tools for retention, legal holds, and eDiscovery.

  • Disaster Recovery: Minimizes downtime with automated failover and quick recovery.

  • Security: Protects against cyber threats, including ransomware.

  • Centralized Management: A single console to manage all backup and recovery operations.


Challenges and Considerations

While Commvault is highly capable, organizations should be aware of potential challenges:

  • Complexity: Large-scale deployments can be complex and require skilled administrators.

  • Cost: Licensing and infrastructure costs can be significant for enterprises with large datasets.

  • Resource Intensive: Backup and deduplication processes may require substantial CPU and memory resources.

  • Learning Curve: Advanced features, such as automation and analytics, require proper training to fully utilize.


Commvault in the Industry

Commvault is recognized as a leader in the data protection and management space by industry analysts like Gartner and Forrester. Organizations across sectors—banking, healthcare, manufacturing, government, and education—rely on Commvault to secure and manage their data. Its integration with cloud providers, virtualization platforms, and enterprise applications makes it a versatile solution for modern IT infrastructures.


Future of Commvault

As data continues to grow exponentially and cybersecurity threats evolve, Commvault is focusing on:

  • AI-driven Data Management: Leveraging machine learning to predict failures, optimize storage, and automate operations.

  • Cloud-Native Backup Solutions: Enhancing multi-cloud and hybrid-cloud support to meet enterprise demands.

  • Ransomware Defense: Improving anomaly detection, immutable storage, and rapid recovery solutions.

  • Automation and Orchestration: Providing automated workflows for backup, recovery, and compliance to reduce administrative overhead.

Fresher Interview Questions

 

1. What is Commvault?

Answer:
Commvault is a data protection and information management software used for backup, recovery, and archive of data in enterprise environments. It helps organizations protect their data across physical, virtual, and cloud environments.

Key points:

  • Ensures data security and compliance.

  • Supports multiple platforms: Windows, Linux, Unix, VMware, Hyper-V, etc.

  • Offers deduplication, encryption, and disaster recovery.


2. What are the main features of Commvault?

Answer:

  • Data Backup: Full, incremental, and differential backups.

  • Data Recovery: Recover files, folders, or entire systems.

  • Snapshot Management: Integrates with storage snapshots.

  • Deduplication: Reduces storage usage.

  • Cloud Integration: Supports AWS, Azure, Google Cloud backups.

  • Encryption & Security: Protects data at rest and in transit.

  • Automation: Schedules backup and recovery jobs automatically.


3. What are the main components of Commvault?

Answer:

  1. CommServe – Central management server, manages all backup and recovery operations.

  2. MediaAgent – Responsible for moving data between clients and storage.

  3. Client – The system or application from which data is backed up.

  4. Storage Devices – Tape libraries, disk storage, or cloud storage used for storing backup data.

  5. CommCell Console – GUI interface for managing all operations.


4. What is the difference between full, incremental, and differential backups?

Answer:

Backup Type Description Advantage
Full Backs up all selected data Simple recovery
Incremental Backs up only data changed since last backup Saves storage and time
Differential Backs up data changed since last full backup Faster recovery than incremental

5. What is a Subclient in Commvault?

Answer:
A Subclient is a subset of data defined under a client in Commvault.

  • It allows granular backup of files, folders, applications, or databases.

  • Example: On a Windows server, you can create subclients for Documents, Pictures, and Database Files separately.


6. What is a Storage Policy?

Answer:
A Storage Policy defines where and how the backup data will be stored. It links the MediaAgent, libraries, and storage paths.

  • Components:

    1. Copy Groups – Rules for data storage.

    2. Libraries – Physical or logical storage devices.

    3. MediaAgent – Manages the data movement.


7. What is a CommServe?

Answer:

  • The CommServe is the central server of a Commvault environment.

  • Responsibilities:

    • Tracks all backup and restore jobs.

    • Stores configuration database.

    • Provides reporting and monitoring.


8. What is a MediaAgent?

Answer:

  • A MediaAgent is a server that transfers data between clients and storage.

  • It handles backup, restore, deduplication, and replication processes.

  • It communicates with CommServe to manage jobs.


9. What is Deduplication?

Answer:
Deduplication is a process of eliminating duplicate copies of data to reduce storage usage.

  • Client-side deduplication: Data is deduplicated before sending to MediaAgent.

  • MediaAgent-side deduplication: Data is deduplicated at the MediaAgent level.


10. What is a Backup Set in Commvault?

Answer:
A Backup Set is a collection of subclients under a client that are backed up together.

  • Example: Database backup set may include multiple subclients for different databases.


11. What is the difference between a Client and a Subclient?

Answer:

Term Definition
Client The system or application from which data is backed up
Subclient A specific portion of the client data (like folders, files, databases)

12. What is a Job in Commvault?

Answer:
A Job is an instance of a backup, restore, or other operation executed in Commvault.

  • Types of jobs: Backup Job, Restore Job, Copy Job, Archive Job

  • Each job is tracked by CommServe for reporting and auditing.


13. What are the common job statuses in Commvault?

Answer:

  • Running: Job is in progress

  • Completed: Job completed successfully

  • Failed: Job failed due to errors

  • Aborted: Job was manually stopped

  • Queued: Job is waiting to start


14. What is a Client Group?

Answer:

  • A Client Group is a collection of multiple clients.

  • Helps schedule backup jobs for multiple clients at once.

  • Reduces administrative overhead.


15. What is a Copy Group?

Answer:

  • A Copy Group defines how backup data is stored for a backup set.

  • Includes rules for retention, storage location, and storage type.

  • Example: Full backup goes to Disk, Incremental backup goes to Tape.


16. What is a Retention Policy?

Answer:

  • Defines how long backup data should be kept before deletion.

  • Types:

    • Simple Retention – Fixed time duration

    • GFS (Grandfather-Father-Son) – Rotational backup retention for long-term storage


17. What is a Synthetic Full Backup?

Answer:

  • A Synthetic Full Backup combines previous full and incremental backups without re-reading client data.

  • Saves network bandwidth and reduces backup time.


18. What are some common backup strategies?

Answer:

  • Full + Incremental (Most common)

  • Full + Differential

  • Synthetic Full + Incremental

  • Incremental Forever


19. What is a Disaster Recovery in Commvault?

Answer:
Disaster Recovery (DR) is the ability to restore data and applications quickly in case of system failure, corruption, or disaster.

  • Commvault supports:

    • Virtual machine restores

    • Bare-metal recovery

    • Cloud DR


20. How is Commvault different from other backup solutions?

Answer:

  • Supports heterogeneous environments (physical, virtual, cloud).

  • Provides deduplication and encryption out-of-the-box.

  • Offers single console management for the entire environment.

  • Supports granular recovery of files, folders, and application items (Exchange, SQL, SharePoint, etc.).


21. What are some troubleshooting steps for failed backup jobs?

Answer:

  • Check job logs in CommCell Console.

  • Verify network connectivity between Client, MediaAgent, and CommServe.

  • Check disk space on storage devices.

  • Verify client or subclient configuration.

  • Retry the job after correcting issues.


22. What is Commvault Edge?

Answer:

  • Commvault Edge is designed for remote and branch offices.

  • Provides centralized management and backup for distributed environments.


23. How do you restore data using Commvault?

Answer:

  1. Open CommCell Console.

  2. Navigate to the client or subclient.

  3. Select the Restore option (File, Folder, Database, VM).

  4. Choose restore destination (original or alternate location).

  5. Click Start Restore.


24. Basic Commvault Commands for Freshers

  • qoperation execute – Execute Commvault operations.

  • qoperation list jobs – List all active or completed jobs.

  • qoperation view job – View detailed job information.

  • qoperation cancel job – Cancel running job.


25. What is a Full Backup vs Incremental Forever Backup?

Answer:

  • Full Backup: Backs up all selected data every time. Consumes more storage and takes more time.

  • Incremental Forever: After the first full backup, only incremental changes are backed up every time.

    • Reduces storage usage.

    • Backup windows are shorter.

    • Requires a synthetic full for restore purposes.


26. What is a GFS (Grandfather-Father-Son) Retention Policy?

Answer:

  • GFS is used for long-term retention.

  • Concept:

    • Son (Weekly) – Keep weekly backups for a short duration.

    • Father (Monthly) – Keep monthly backups for medium duration.

    • Grandfather (Yearly) – Keep yearly backups for a long duration (years).

  • Ensures compliance and archival requirements are met.


27. What are the types of Subclients in Commvault?

Answer:

  1. File System Subclient: Backs up files and folders on servers.

  2. Application Subclient: Backs up applications like SQL, Exchange, SharePoint.

  3. Virtual Machine Subclient: Backs up VMware or Hyper-V virtual machines.

  4. Database Subclient: Backups for Oracle, MySQL, or other DBs.


28. How do you configure a Backup Set?

Answer:
Steps:

  1. Open CommCell Console → Client → Create Backup Set.

  2. Choose backup type (File System, Application, Database).

  3. Add Subclients under the backup set.

  4. Assign Storage Policy and Retention Policy.

  5. Schedule backup jobs.


29. What is the difference between Online Backup and Snapshot Backup?

Answer:

Feature Online Backup Snapshot Backup
Data capture Files and applications live Storage-level snapshots
Impact on performance Minimal Depends on storage solution
Granularity File/folder/application level Full volume/block level
Restore Flexible Fast but less granular

30. What is a Synthetic Full and why is it used?

Answer:

  • Synthetic Full Backup is created by merging previous full and incremental backups at the MediaAgent without re-reading data from the client.

  • Benefits:

    • Reduces network bandwidth.

    • Reduces load on client machines.

    • Faster recovery preparation.


31. What is an Auxiliary Copy in Commvault?

Answer:

  • Auxiliary Copy is used to duplicate backup data to another storage target.

  • Purpose: Disaster recovery, offsite storage, and compliance.

  • Example: Backup to disk first → Auxiliary copy to tape/cloud.


32. What is the difference between Backup Copy and Restore Copy?

Answer:

Term Description
Backup Copy Secondary copy of the primary backup for DR or compliance
Restore Copy Backup used specifically to restore data if primary fails

33. What is a Storage Policy Copy?

Answer:

  • A copy under a storage policy defines where and how data is stored.

  • Example:

    • Primary copy: Disk storage.

    • Secondary copy: Tape or cloud.


34. What is MediaAgent vs Storage Library?

Answer:

  • MediaAgent: Handles data movement and communication between client and storage.

  • Storage Library: Physical or virtual storage (disk/tape/cloud) where backup data resides.


35. How do you monitor jobs in Commvault?

Answer:

  • Use CommCell Console → Job Controller to monitor running, queued, or completed jobs.

  • Check Job History for past job details.

  • Job logs provide errors, warnings, and performance stats.

  • Alerts can be configured via email/SNMP.


36. What is the difference between Clone Copy and DR Copy?

Answer:

Feature Clone Copy DR Copy
Purpose Testing or migration Disaster recovery
Update frequency Optional Often scheduled regularly
Location Any storage Offsite or secondary storage

37. How do you perform a File Level Restore (FLR)?

Answer:

  1. Open CommCell Console.

  2. Navigate to Client → Subclient → Restore.

  3. Choose File Level Restore option.

  4. Select files/folders to restore.

  5. Select destination (original location or alternate).

  6. Click Start Restore.


38. How do you handle failed backup jobs?

Answer:

  • Check logs: View Job Details and Event Viewer.

  • Verify network: Ensure client-server connectivity.

  • Check storage: Verify MediaAgent storage availability.

  • Retry job: After fixing errors, restart the job.

  • Check client status: Ensure services and agents are running.


39. What is a Storage Lifecycle Policy (SLP)?

Answer:

  • SLP defines how long backup data is kept and where it moves over time.

  • Example:

    • Disk → Tape → Cloud → Delete after X years.

  • Ensures cost-efficient data management.


40. What is IntelliSnap in Commvault?

Answer:

  • IntelliSnap integrates with storage arrays to take hardware-level snapshots.

  • Benefits:

    • Faster backups.

    • Minimal impact on production systems.

    • Supports application-consistent snapshots.


41. How is Commvault integrated with VMware?

Answer:

  • VMware VM backups are done using VMware vSphere API.

  • Commvault allows:

    • Full VM backups

    • Incremental VM backups using CBT (Changed Block Tracking)

    • VM restore at file-level or full VM level


42. How is Commvault integrated with Microsoft Exchange?

Answer:

  • Exchange subclients are created per database or mailbox.

  • Supports:

    • Mailbox-level restore

    • Database-level restore

    • Granular item-level restore


43. What is Multi-Stream Backup?

Answer:

  • Multiple streams write data simultaneously to MediaAgent or storage.

  • Benefits:

    • Faster backup performance.

    • Reduces backup window for large datasets.


44. What are some common error codes and their meanings?

  • 3025: Network connectivity issues.

  • 3101: Storage library not available.

  • 4012: Backup job failed due to insufficient space.

  • 4100: MediaAgent not reachable.


45. Basic commands for Commvault CLI (qoperation):

  • qoperation execute -af <xmlfile> → Run a job via XML script.

  • qoperation list jobs → List all jobs.

  • qoperation view job -jobid <id> → View details of a specific job.

  • qoperation cancel job -jobid <id> → Cancel a running job.


46. What is the difference between Backup and Archive in Commvault?

Answer:

  • Backup: Copies of data to protect against loss. Typically short-term retention.

  • Archive: Long-term storage of data that is infrequently accessed. Helps with compliance and storage optimization.

  • Key point: Archived data can be restored anytime, but usually slower than backup restores.


47. What is cloud backup in Commvault?

Answer:

  • Commvault supports backup to public cloud storage like AWS S3, Azure Blob, Google Cloud Storage.

  • Features:

    • Secure transfer via encryption.

    • Deduplication before cloud upload.

    • Policy-based retention and replication.

  • Use-case: Offsite storage for disaster recovery and compliance.


48. How do you backup VMware VMs using Commvault?

Answer:

  1. Install Commvault agent on vCenter or ESXi host.

  2. Create VM subclient for selected VMs.

  3. Assign Storage Policy and Retention Policy.

  4. Schedule backup using full, incremental, or synthetic full.

  5. For incremental backup, use CBT (Changed Block Tracking) to speed up backup.


49. How do you restore a VMware VM using Commvault?

Answer:

  • Options for restore:

    1. Full VM Restore – Restores entire VM to original or alternate host.

    2. File Level Restore (FLR) – Restore individual files from VM.

    3. Instant Restore / Mount – Mount VM directly from backup for immediate use.


50. How do you backup Microsoft Exchange with Commvault?

Answer:

  1. Create an Exchange Subclient for each mailbox or database.

  2. Assign backup set and storage policy.

  3. Schedule backup (full/incremental).

  4. Restore options:

    • Mailbox level

    • Database level

    • Individual emails or folders


51. How do you restore a mailbox or email item in Commvault?

Answer:

  1. Open CommCell Console → Client → Exchange Subclient → Restore.

  2. Choose Mailbox or Item Restore.

  3. Select destination: original mailbox or PST file.

  4. Start the restore job.


52. What is Changed Block Tracking (CBT) in VMware backups?

Answer:

  • CBT tracks changed blocks in VMs since the last backup.

  • Only changed blocks are backed up during incremental backups.

  • Benefits:

    • Reduces backup time.

    • Reduces storage and network usage.


53. What is the difference between Hot Backup and Cold Backup?

Answer:

Feature Hot Backup Cold Backup
Backup during active system Yes No
Data consistency Application-aware Application may be offline
Use-case Databases, Exchange, SQL File system backup during downtime

54. How does Commvault handle Database backups (SQL/Oracle)?

Answer:

  • Install Commvault agent on DB server.

  • Create DB subclient for selected databases.

  • Supports full, incremental, and transaction log backups.

  • Enables point-in-time restore using transaction logs.


55. What is a Disaster Recovery (DR) plan in Commvault?

Answer:

  • DR plan ensures quick restoration in case of system failure or disaster.

  • Commvault supports:

    • VM replication

    • Offsite backups

    • Auxiliary copies to tape or cloud

  • Regular DR drills ensure recovery readiness.


56. What are some common reasons for backup failures?

Answer:

  • Network connectivity issues between client, MediaAgent, and CommServe.

  • Storage device full or unavailable.

  • Permission issues on client files/folders.

  • Commvault services not running.

  • Incorrect subclient or storage policy configuration.


57. How to troubleshoot failed backup jobs?

Answer:

  1. Check job logs and event viewer for errors.

  2. Verify client and MediaAgent connectivity.

  3. Check disk space and storage availability.

  4. Ensure Commvault services are running.

  5. Retry job after fixing the root cause.


58. What is IntelliSnap in Commvault?

Answer:

  • IntelliSnap creates hardware-level snapshots of storage volumes.

  • Benefits:

    • Application-consistent snapshots.

    • Minimal impact on production systems.

    • Fast backup and restore.

  • Works with VMs, databases, and file servers.


59. What is Multi-Stream Backup and why is it used?

Answer:

  • Multi-stream backup splits data into multiple parallel streams.

  • Each stream writes to MediaAgent or storage simultaneously.

  • Benefits:

    • Faster backup performance.

    • Reduces backup window for large datasets.


60. Explain the concept of Auxiliary Copy and how it is different from Storage Policy Copy.

Answer:

  • Auxiliary Copy: Secondary copy of existing backup data for DR or compliance.

  • Storage Policy Copy: Defines primary and secondary storage for the backup set.

  • Difference: Auxiliary copy is post-backup duplication, while Storage Policy copy is part of the backup process.


61. How do you handle cloud storage backup and restore in Commvault?

Answer:

  • Configure cloud storage target in Storage Policy.

  • Enable deduplication and encryption.

  • Backup jobs send data to cloud bucket.

  • Restore can be done to original client or alternate location.


62. How do you monitor storage and job performance in Commvault?

Answer:

  • CommCell Console → Reports → Job/Storage Reports.

  • Check metrics like:

    • Job duration

    • Throughput (MB/s)

    • Storage utilization

    • Failed/successful job ratio


63. What are common Commvault services and their purpose?

Answer:

  • CommServe Service: Central management.

  • MediaAgent Service: Handles data movement.

  • Client Services: Runs backup agents on servers.

  • Edge Services: Manages remote/branch office clients.


64. Scenario Question: “A backup job fails with 3025 error. How do you troubleshoot?”

Answer:

  1. Error 3025 → Network connectivity issue.

  2. Check ping and firewall rules between client and MediaAgent.

  3. Verify Commvault services are running on client and MediaAgent.

  4. Check port availability and network routes.

  5. Retry job after resolving connectivity.

Experienced Interview Questions

 

1. Explain the Commvault architecture in detail.

Answer:
Commvault has a modular architecture comprising the following components:

  • CommServe: Central management server that coordinates all backup, restore, and reporting tasks.

  • MediaAgent (MA): Responsible for reading/writing backup data to storage.

  • Client: Any system (Windows, Linux, DB, Virtual Machine) protected by Commvault agent.

  • CommCell Console: GUI or CLI to manage the entire environment.

  • Storage Devices: Disk, tape, or cloud storage for backup data.

  • Deduplication Engine: Reduces storage consumption by eliminating duplicate data.

Scenario: In large enterprises, multiple MediaAgents handle backups to multiple storage targets, while CommServe manages policies, schedules, and reporting.


2. What is a Commvault Subclient and why is it used?

Answer:

  • Subclient: Logical partition of a client that defines specific data to be backed up.

  • Allows granular control of backup operations (files, folders, database tables, VMs).

  • Each subclient can have independent schedules, retention policies, and storage policies.

Scenario: Backing up only /home folder in Linux instead of entire filesystem to optimize backup window.


3. What are Storage Policies in Commvault?

Answer:

  • Defines where and how backup data is stored.

  • Comprises Primary Storage Policy (short-term) and Secondary Storage Policy (long-term/archive).

  • Determines MediaAgent, device, retention, and backup copy rules.

Scenario: A SQL Server backup might use a high-performance disk primary storage and a tape secondary for long-term retention.


4. Explain the difference between Full, Incremental, and Differential backups in Commvault.

Answer:

Backup Type Description
Full Backs up all selected data regardless of previous backups
Incremental Backs up only data changed since the last backup (full or incremental)
Differential Backs up data changed since last full backup

Scenario: Incremental backups reduce storage and network usage, while full backups are needed periodically for complete restore points.


5. How does Commvault handle deduplication?

Answer:

  • Deduplication can occur at source (client-side) or target (MediaAgent).

  • Reduces storage and network usage by storing only unique data blocks.

  • Deduplication is configurable in Storage Policy.

Scenario: Backup of 500 VMs with similar OS files only stores unique blocks once.


6. What is a MediaAgent and its role?

Answer:

  • MediaAgent (MA): Handles all data movement between client and storage.

  • Responsible for backup, restore, data deduplication, and index management.

  • Can manage multiple storage devices and share load in large environments.

Scenario: For high-volume VMware backups, multiple MediaAgents distribute the load.


7. Explain Commvault Job Types.

Answer:

  • Backup Jobs: Full, incremental, or differential backups.

  • Restore Jobs: Recover data from primary or secondary storage.

  • Archive Jobs: Move inactive data to secondary storage for retention.

  • Replication Jobs: Copy backup data from one storage device to another.

  • Synthetic Full Jobs: Combine incremental backups with previous full backup to create a new full backup without reading the client data.


8. What is a CommCell in Commvault?

Answer:

  • CommCell: Logical representation of the Commvault environment, including:

    • CommServe

    • MediaAgents

    • Clients

    • Storage policies

    • Jobs, schedules, and reports

  • Provides centralized management through GUI or CLI.


9. How do you configure backup schedules in Commvault?

Answer:

  • Schedules can be configured at the Subclient or Storage Policy level.

  • Types of schedules:

    • Daily, Weekly, Monthly

    • Time-window-based schedules to avoid production hours

  • Commvault supports multiple concurrent schedules for different clients or subclients.

Scenario: Critical databases backed up every hour incrementally and a full backup nightly.


10. What is Synthetic Full Backup in Commvault?

Answer:

  • Creates a full backup without reading all client data.

  • Combines previous full backup and incremental backups stored on disk.

  • Reduces network usage and client load.

Scenario: Large database backups use synthetic full to optimize backup window.


11. Explain Commvault deduplication storage techniques.

Answer:

  1. Client-side deduplication: Reduces network load by sending only unique data blocks.

  2. Target-side deduplication: Saves disk space on MediaAgent storage.

  3. Deduplication databases: Track unique blocks for indexing and restores.


12. How do you monitor Commvault jobs and performance?

Answer:

  • Use CommCell Console or Job Controller to monitor jobs.

  • Track:

    • Job status (Success, Warning, Failed)

    • Throughput (MB/s)

    • Errors and retries

  • Use reports and dashboards for long-term performance trends.

Scenario: Identify slow backup performance due to network or storage bottlenecks.


13. What are Commvault Streams and how are they used?

Answer:

  • Streams define number of concurrent threads for backup/restore.

  • Configurable per subclient or job.

  • Helps optimize network and storage performance.

Scenario: High-throughput VMware backups require increasing the number of streams per VM to reduce backup window.


14. Explain Commvault's Data Aging and Retention Policy.

Answer:

  • Determines how long backup data is retained on primary and secondary storage.

  • Retention rules: Days, Weeks, Months, or Years.

  • Can be configured per subclient or storage policy.

  • Helps comply with legal or organizational retention requirements.

Scenario: Financial data kept 7 years on tape, while daily VM backups kept 30 days on disk.


15. How do you troubleshoot Commvault failed jobs?

Answer:

  1. Check job status and error codes in CommCell Console.

  2. Review job logs on client and MediaAgent.

  3. Verify network connectivity between client, MA, and storage.

  4. Check permissions on storage and access to devices.

  5. Validate schedules and backup policies.

Scenario: Incremental job fails due to locked database files—enable VSS or application-aware backup.


16. How do you perform a disaster recovery using Commvault?

Answer:

  • Restore CommServe database to rebuild environment.

  • Restore MediaAgent data if needed.

  • Recover critical client data from primary or secondary storage.

  • Test restores in staging to ensure DR readiness.

Scenario: In case of server failure, restore critical VMs and SQL databases from tape or cloud backups.


17. How do you backup Virtual Machines in Commvault?

Answer:

  • VMware, Hyper-V, and Nutanix supported.

  • Subclient created per VM or VM group.

  • Backup types: Full, Incremental, Synthetic Full, CBT (Changed Block Tracking).

  • Enable application-aware backup for database or exchange VMs.

Scenario: VMware VM backup with CBT reduces backup window and storage usage.


18. Explain Commvault encryption techniques.

Answer:

  • AES 256-bit encryption at client-side or MediaAgent.

  • Data can be encrypted during transit (network) and at rest (disk/tape).

  • Use encryption keys managed centrally or per client.

Scenario: Protect sensitive financial or healthcare data as per compliance requirements.


19. How do you integrate Commvault with Cloud Storage?

Answer:

  • Commvault supports AWS S3, Azure Blob, Google Cloud Storage, and IBM Cloud.

  • Configure Cloud Storage Policy and MediaAgent.

  • Supports Tiering, Archive, and DR replication to cloud.

Scenario: Cold storage for infrequently accessed backup data using S3 Glacier.


20. Explain Commvault Deduplication Database (DDB).

Answer:

  • DDB stores metadata about unique blocks.

  • Enables deduplication at source or target.

  • Supports indexing for restores.

  • DDB corruption can lead to failed restores; regular DDB maintenance is critical.


21. How do you handle large-scale Commvault environments?

Answer:

  • Deploy multiple MediaAgents to distribute load.

  • Use Storage Policies for tiered storage.

  • Optimize Streams and job concurrency.

  • Monitor job performance and throughput.

  • Regularly maintain deduplication databases and indexes.

Scenario: Enterprise environment with thousands of clients, VMs, and applications.


22. How do you restore application-aware backups?

Answer:

  • Enable application-aware backup (e.g., SQL, Exchange, Oracle) using agents.

  • Restore databases using Granular Recovery Technology (GRT).

  • Supports point-in-time recovery, transaction logs, and mailbox-level restores.


23. Explain Commvault Synthetic Full vs Traditional Full.

Answer:

Feature Synthetic Full Traditional Full
Client Impact Low (combines previous backups) High (reads all data)
Network Usage Minimal High
Storage Usage Same as traditional Same
Backup Window Shorter Longer

24. How do you monitor and optimize backup performance?

Answer:

  • Track MB/sec throughput in CommCell Console.

  • Adjust streams, concurrency, and schedule windows.

  • Optimize client, MediaAgent, and storage resource allocation.

  • Use reports to identify slow jobs.


25. How do you troubleshoot cloud backup failures?

Answer:

  1. Verify network connectivity to cloud endpoint.

  2. Check authentication and IAM policies.

  3. Ensure cloud storage bucket exists and has proper permissions.

  4. Inspect job logs for errors (like throttling or timeouts).

Scenario: AWS S3 backup failing due to insufficient IAM permissions.


26. How do you configure Commvault for disaster recovery (DR)?

Answer:

  • CommServe DR: Set up a standby CommServe server at a remote site with replicated database.

  • MediaAgent DR: Deploy additional MediaAgents in DR site for storage access.

  • Storage replication: Use secondary storage policies or cloud replication.

  • Testing: Perform regular DR drills to verify restore capabilities.

Scenario: Restore critical applications within SLA in case of primary site failure.


27. How do you perform bare-metal restore using Commvault?

Answer:

  • Install CommCell agent on target hardware.

  • Restore system state or disk image to new hardware.

  • Use Hardware Independent Restore (HIR) to adapt drivers and storage configuration.

Scenario: Rebuild failed physical server with minimal downtime.


28. How do you configure multi-site Commvault environments?

Answer:

  • Deploy CommServe at primary site, with DR/replica CommServe at secondary.

  • Multiple MediaAgents in each site.

  • Configure storage policies for local and remote storage.

  • Use Replication Jobs to copy backup data between sites.

Scenario: Enterprises with primary and disaster recovery datacenters.


29. How do you backup SQL Server using Commvault?

Answer:

  • Install Commvault SQL agent.

  • Create subclients for databases.

  • Configure backup type: full, incremental, log backups.

  • Enable transaction log backup for point-in-time recovery.

  • Use GRT for granular restores of tables, rows, or objects.


30. How do you restore Oracle databases with Commvault?

Answer:

  • Use Oracle agent with RMAN integration.

  • Backup types: full, incremental, archive logs.

  • Restore can be full database, tablespace, or individual table objects.

  • Supports Point-in-Time Recovery (PITR) using archived logs.


31. How do you perform Commvault granular recovery for Exchange or SharePoint?

Answer:

  • Enable GRT (Granular Recovery Technology).

  • Backup Exchange or SharePoint subclients.

  • Restore individual mailboxes, emails, SharePoint lists, or documents without full database restore.

Scenario: Recover a single user mailbox without affecting production.


32. How do you integrate Commvault with cloud providers?

Answer:

  • Supported cloud: AWS S3/Glacier, Azure Blob, GCP, IBM Cloud.

  • Configure Cloud Storage Policies in Commvault.

  • Supports backup, archive, tiering, and DR replication.

  • Use encryption and compression for secure, optimized storage.

Scenario: Move old backups to AWS Glacier for long-term cost savings.


33. How do you handle large-scale VMware backups?

Answer:

  • Use VMware Agent or VMware CBT (Changed Block Tracking).

  • Configure subclients per VM or per VM group.

  • Use multiple MediaAgents for load balancing.

  • Enable Synthetic Full Backup to reduce backup window.

Scenario: Backup 500+ VMs in an enterprise cluster with minimal disruption.


34. How do you manage Commvault deduplication databases (DDB) for large environments?

Answer:

  • Ensure DDB size is appropriate for data volume.

  • Regular database maintenance and integrity checks.

  • Monitor DDB growth trends to avoid storage exhaustion.

  • Optimize MediaAgent allocation for deduplication.

Scenario: Enterprise environment with multiple petabytes of backup data.


35. How do you troubleshoot backup performance issues in Commvault?

Answer:

  • Check MediaAgent throughput and job streams.

  • Verify network bandwidth between clients and MediaAgents.

  • Inspect deduplication ratios and DDB performance.

  • Optimize job schedules to avoid overlapping heavy backups.

  • Review storage device performance (disk, tape, cloud).


36. How do you perform restores from cloud backups?

Answer:

  • Use Cloud Storage Policy to locate backups.

  • Restore to original client or alternate location.

  • Ensure network throughput is sufficient for large restores.

  • Optionally, restore to on-premises MediaAgent before production deployment.

Scenario: Recover VM from AWS S3 backup to on-premises hypervisor.


37. How do you implement backup encryption in Commvault?

Answer:

  • Configure AES-256 encryption at client, MediaAgent, or storage level.

  • Manage encryption keys centrally or per subclient.

  • Supports encryption in transit (network) and at rest (disk/tape/cloud).

Scenario: Protect sensitive data like financial or healthcare information.


38. How do you perform backup verification in Commvault?

Answer:

  • Enable Backup Verification option for subclients.

  • Options include mount verification, checksum verification, and restore simulation.

  • Ensures backup integrity and recoverability.

Scenario: Critical databases require verified backups before month-end reporting.


39. How do you handle incremental forever backup strategy?

Answer:

  • Full backup performed once.

  • Subsequent backups are incremental only.

  • Synthetic full or scheduled full backups can be created if needed.

  • Reduces network load and backup window.


40. How do you monitor Commvault reports and alerts?

Answer:

  • Use CommCell Console to view job summaries, trends, and alerts.

  • Generate custom reports for SLA compliance, storage usage, and job success/failure trends.

  • Configure email alerts or SNMP notifications for failed jobs or storage issues.


41. How do you configure Commvault for tape backups?

Answer:

  • Define tape library or standalone drive as storage device.

  • Create Storage Policy pointing to tape.

  • Schedule backups to use tape media.

  • Configure retention and offsite rotation for long-term storage.

Scenario: Archive monthly backups for regulatory compliance.


42. How do you perform disaster recovery for a Commvault CommServe database?

Answer:

  • Backup CommServe database regularly using SQL or Commvault built-in backup.

  • Restore the database to standby CommServe server or alternate site.

  • Reconfigure MediaAgents and clients if DR site is used.

  • Validate restore functionality before production use.


43. How do you handle Commvault agent failures?

Answer:

  • Check agent logs on the client system.

  • Verify network connectivity to CommServe and MediaAgent.

  • Restart agent services if needed.

  • Reinstall agent if corruption is detected.

  • Check for permissions or firewall issues.


44. How do you perform Commvault database backup and restore?

Answer:

  • Use database agent for SQL, Oracle, MySQL, or other supported DBs.

  • Configure full, incremental, or log backups.

  • Restore full database or individual tables using GRT if supported.

  • Supports point-in-time recovery using transaction logs.


45. How do you handle Commvault licensing for enterprise environments?

Answer:

  • Licenses are typically capacity-based or client-based.

  • Monitor usage per client, media, or TBs.

  • Assign licenses to agents and MediaAgents using CommCell Console.

  • Ensure compliance to avoid job failures.


46. How do you integrate Commvault with VMware vCenter?

Answer:

  • Install VMware agent on CommServe or MediaAgent.

  • Add vCenter server credentials in Commvault.

  • Discover VMs and create subclients per VM or folder.

  • Enable Changed Block Tracking (CBT) for incremental backups.

Scenario: Automates VM backups in large vSphere environments efficiently.


47. How do you implement multi-tenancy in Commvault?

Answer:

  • Create separate CommCell users and roles for different teams.

  • Assign storage policies and subclients per tenant.

  • Restrict access using CommCell permissions and role-based access control.

Scenario: Service provider managing multiple clients using single Commvault environment.


48. How do you perform Commvault restore to an alternate location?

Answer:

  • Use Restore Options to select alternate path, client, or VM host.

  • Useful for testing restores without affecting production.

  • Supports redirecting database restores to alternate SQL instance.


49. How do you handle SLA-based backups in Commvault?

Answer:

  • Define backup schedules, retention, and storage policies to meet SLA.

  • Monitor job completion time and throughput.

  • Use reporting and alerts to track SLA compliance.

Scenario: Critical applications must complete backup within 2 hours every night.


50. How do you perform advanced troubleshooting for Commvault performance issues?

Answer:

  • Check MediaAgent CPU, memory, and disk I/O.

  • Analyze job logs and job history for errors.

  • Monitor deduplication performance and DDB size.

  • Check network latency and throughput between clients and MediaAgents.

  • Tune streams, concurrency, and synthetic full settings.