What Is a RAID Array? A Complete Guide for Data Protection and Performance

Updated on February 10, 2026, by Xcitium

Data loss is one of the most expensive and disruptive problems an organization can face. Whether it’s caused by hardware failure, cyberattacks, or human error, losing critical data can halt operations and damage trust. That’s why many IT teams ask an essential question: what is a RAID array, and how does it help protect data?

A RAID array is a foundational technology used in servers, storage systems, and enterprise environments to improve performance, reliability, or both. While RAID is not a replacement for backups, it plays a critical role in data availability and system resilience.

In this guide, we’ll explain what a RAID array is, how it works, different RAID levels, benefits and limitations, cybersecurity considerations, and best practices for modern IT environments.

What Is a RAID Array?

A RAID array is a storage configuration that combines multiple physical hard drives into a single logical unit to improve data performance, redundancy, or both.

RAID stands for Redundant Array of Independent Disks. Instead of relying on one drive, RAID spreads data across multiple disks using specific methods called RAID levels.

In simple terms:

RAID uses multiple drives
Data is distributed in a controlled way
The system appears as one storage unit

This approach helps protect against hardware failure and improve system efficiency.

Why RAID Arrays Are Important

Understanding what is a RAID array starts with understanding why organizations use them.

Key reasons RAID arrays are used:

Reduce downtime caused by disk failure
Improve read and write performance
Increase data availability
Support mission-critical workloads

For businesses, uptime and data access are just as important as data security.

How Does a RAID Array Work?

A RAID array works by distributing data across multiple drives in different ways depending on the RAID level.

Core RAID techniques include:

Striping – Splits data across disks for speed
Mirroring – Copies data across disks for redundancy
Parity – Stores calculated data to rebuild lost information

Different RAID levels use one or more of these techniques.

Types of RAID Arrays: Hardware vs Software RAID

Before choosing a RAID configuration, it’s important to understand implementation types.

Hardware RAID

Hardware RAID uses a dedicated controller to manage the array.

Advantages:

Better performance
Less load on the CPU
More reliable for enterprise use

Disadvantages:

Higher cost
Hardware dependency

Software RAID

Software RAID is managed by the operating system.

Advantages:

Lower cost
Flexible configuration
No specialized hardware required

Disadvantages:

Uses system resources
Performance depends on OS

Both approaches are widely used depending on environment needs.

Common RAID Levels Explained

To fully answer what is a RAID array, you must understand RAID levels.

RAID 0 – Performance Only

How it works:

Data is striped across disks
No redundancy

Pros:

Maximum performance
Full storage utilization

Cons:

No fault tolerance
One drive failure = total data loss

RAID 0 is fast but risky.

RAID 1 – Mirroring for Redundancy

How it works:

Data is mirrored across two disks

Pros:

High data protection
Easy recovery

Cons:

Uses 50% of total storage

RAID 1 is common in systems where availability matters.

RAID 5 – Balanced Performance and Protection

How it works:

Data and parity distributed across drives
Requires at least three disks

Pros:

Fault tolerance
Efficient storage usage

Cons:

Slower writes
Longer rebuild times

RAID 5 is widely used but less favored for large drives today.

RAID 6 – Enhanced Fault Tolerance

How it works:

Similar to RAID 5 but with dual parity

Pros:

Can survive two drive failures
Good for large arrays

Cons:

Slower write performance
More complex

RAID 6 is common in enterprise storage systems.

RAID 10 – Performance and Redundancy

How it works:

Combines RAID 1 and RAID 0
Requires at least four disks

Pros:

Excellent performance
Strong redundancy

Cons:

Higher cost
Reduced usable capacity

RAID 10 is ideal for databases and critical workloads.

RAID Array Use Cases in Modern IT

Understanding what is a RAID array also means knowing where it’s used.

Common use cases:

Servers and data centers
Network-attached storage (NAS)
Database systems
Virtualization platforms
High-performance applications

RAID ensures systems stay operational even during hardware failures.

RAID Array vs Backup: Understanding the Difference

One of the most common misconceptions is that RAID replaces backups.

RAID:

Protects against disk failure
Maintains availability
Does not protect against deletion or ransomware

Backup:

Protects against data loss
Enables recovery from many scenarios
Does not guarantee uptime

RAID and backup serve different but complementary purposes.

RAID Arrays and Cybersecurity

From a cybersecurity perspective, what is a RAID array goes beyond performance.

Security considerations:

RAID does not prevent cyberattacks
Ransomware affects RAID volumes
Data corruption is mirrored across disks

RAID improves availability—not security.

RAID and Ransomware Risks

RAID arrays can actually worsen ransomware impact.

Why:

Encrypted data is written to all disks
Parity data becomes useless
Recovery requires clean backups

Security controls must be layered on top of RAID.

RAID Arrays in Compliance and Governance

Regulated industries often rely on RAID.

Compliance benefits:

Improved availability
Reduced downtime
Support for business continuity

However, compliance still requires encryption, monitoring, and backups.

Performance Considerations When Using RAID

RAID performance depends on configuration.

Factors affecting performance:

RAID level
Disk type (HDD vs SSD)
Controller quality
Workload type

Choosing the wrong RAID level can bottleneck systems.

RAID Arrays and Cloud Environments

Cloud platforms abstract RAID details.

Cloud considerations:

Providers manage underlying RAID
Users focus on redundancy at higher levels
Shared responsibility still applies

Even in the cloud, understanding RAID concepts is valuable.

Common RAID Array Mistakes

Many organizations misuse RAID.

Common mistakes:

Assuming RAID equals backup
Choosing outdated RAID levels
Ignoring rebuild risks
Mixing disk types

Proper planning prevents these issues.

Best Practices for RAID Array Deployment

To get the most from a RAID array, follow best practices.

Recommended best practices:

Choose RAID level based on workload
Use identical disks
Monitor disk health
Maintain verified backups
Test recovery procedures

RAID is strongest when combined with good operational discipline.

RAID Rebuilds: Risks and Considerations

Rebuilding a RAID array is stressful.

Rebuild risks include:

Performance degradation
Second disk failure
Extended rebuild times

Modern large disks increase rebuild risk, making RAID selection critical.

RAID Arrays for Small vs Large Organizations

RAID use varies by organization size.

Small businesses:

Simple RAID 1 or RAID 10
Focus on affordability and reliability

Enterprises:

RAID 6 or RAID 10
Advanced monitoring and automation

Scale changes the risk profile.

Future of RAID Technology

RAID continues to evolve.

Emerging trends:

SSD-optimized RAID
Software-defined storage
Cloud-integrated redundancy
Enhanced error correction

RAID remains relevant despite new storage technologies.

FAQs: What Is a RAID Array?

1. What is a RAID array used for?

A RAID array improves performance, reliability, or both by using multiple disks together.

2. Is RAID the same as backup?

No. RAID protects against hardware failure, not data loss events.

3. Which RAID level is best?

It depends on performance, redundancy, and budget needs.

4. Can RAID protect against ransomware?

No. Backups and security controls are still required.

5. Do SSDs need RAID?

Yes, RAID can improve performance and availability even with SSDs.

Final Thoughts: Is a RAID Array Still Worth It?

Understanding what is a RAID array helps organizations build resilient, high-performing storage systems. While RAID is not a complete data protection solution, it remains a critical layer in modern IT infrastructure.

When implemented correctly, RAID: