Hexworth Prime House of Forge

RAID & Storage Configuration

CompTIA A+ Core 1 (220-1101) • Domain 3.0 Hardware
Key Concepts: RAID 0 RAID 1 RAID 5 RAID 10 Hardware vs Software

What is RAID?

RAID (Redundant Array of Independent Disks) combines multiple physical drives into a single logical unit for improved performance, redundancy, or both.

A+ Exam Tip: RAID is NOT a backup solution! It provides fault tolerance but won't protect against user error, malware, or catastrophic failures. Always maintain separate backups.

RAID 0 - Striping

A1
A2
A3
A4
Data stripe

Advantages

  • Maximum performance (read/write)
  • 100% storage efficiency
  • Easy to implement

Disadvantages

  • NO fault tolerance
  • One drive failure = total data loss
  • Higher risk than single drive
Min Drives: 2 | Capacity: N × smallest drive | Use Case: Video editing, gaming (where speed > safety)

RAID 1 - Mirroring

A
A
or
A
A
A
A
Mirrored data (identical copies)

Advantages

  • Full redundancy (1 drive can fail)
  • Fast read performance
  • Simple recovery

Disadvantages

  • 50% storage efficiency
  • Write speed = single drive
  • Expensive per GB
Min Drives: 2 | Capacity: N/2 × smallest drive | Use Case: OS drives, critical data, small servers

RAID 5 - Striping with Parity

A1
A2
P
B1
P
B2
P
C1
C2
Data
Parity (distributed)

Advantages

  • Good balance of speed/redundancy
  • Can survive 1 drive failure
  • Better efficiency than RAID 1

Disadvantages

  • Slower writes (parity calculation)
  • Long rebuild times
  • Vulnerable during rebuild
Min Drives: 3 | Capacity: (N-1) × smallest drive | Use Case: File servers, general purpose

RAID 10 (1+0) - Mirrored Stripes

A1
A1
Mirror 1
+
A2
A2
Mirror 2
Mirrored pairs striped together

Advantages

  • Best performance + redundancy
  • Can lose 1 drive per mirror pair
  • Fast rebuilds

Disadvantages

  • 50% storage efficiency
  • Requires minimum 4 drives
  • Most expensive option
Min Drives: 4 | Capacity: N/2 × smallest drive | Use Case: Databases, enterprise, high-performance servers

RAID Comparison Chart

RAID Min Drives Fault Tolerance Efficiency Read Speed Write Speed
RAID 0 2 None 100% Excellent Excellent
RAID 1 2 1 drive 50% Good Normal
RAID 5 3 1 drive (N-1)/N Good Moderate
RAID 6 4 2 drives (N-2)/N Good Slow
RAID 10 4 1 per pair 50% Excellent Good

Hardware vs Software RAID

Hardware RAID

  • Dedicated RAID controller card
  • Has own processor and cache
  • Better performance
  • OS-independent
  • Higher cost
  • Battery backup unit (BBU) option

Software RAID

  • Uses CPU for RAID operations
  • Built into OS (Windows/Linux)
  • Lower cost (no extra hardware)
  • Easier to migrate between systems
  • CPU overhead
  • Windows: Storage Spaces, Dynamic Disks
Fake RAID: Some motherboard "RAID" is actually software RAID using firmware. True hardware RAID has a dedicated processor on the controller card.

Knowledge Check

Q1: Which RAID level provides NO fault tolerance but maximum performance?

Q2: You have 4 × 1TB drives in RAID 5. What is the usable capacity?

Q3: Which RAID level combines mirroring and striping, requiring a minimum of 4 drives?

Q4: What is one disadvantage of software RAID compared to hardware RAID?