What is a Disk Array?

A disk array is a storage system that combines multiple disk drives (HDD or SSD) to improve data storage performance, capacity, and reliability. There are several ways to configure drives into a disk array, the most common being RAID (Redundant Array of Independent Disks).

 

Main Purposes of a Disk Array:

  • Fault Tolerance: Data remains intact even if some drives fail.
  • Performance Improvement: Parallel read/write across multiple drives accelerates access speed.
  • Storage Scalability: Capacity can be easily expanded.
  • Centralized Management: Simplifies system architecture and data management.

 

Common RAID Levels

RAID Level Comparison N = Number of Drives

 RAID 0RAID 1RAID 5RAID 6
Minimum Number of Drives2234
Speed & PerformanceHighMediumMedium-HighMedium
Usable CapacityN1N-1N-2
ReliabilityNone
(One drive failing affects all data)		High
(One functioning drive is enough)		Medium
(One drive failure allowed)		Medium-High
(Two drive failures allowed)
Fault Tolerance0N-112
Features
Performance-focusedNo Protection
Mirrored BackupMost Secure
Balanced Speed & SecuritySlightly Lower Write Performance
Suitable for Large SystemsHigher Cost

ARAID RAID Enclosure vs RAID Card Comparison

ARAID RAID Enclosure

RAID Card
Operates independently
No OS/driver dependency
System Dependency
Highly dependent on BIOS, drivers, and OS
External type (5.25" bay or standalone enclosure)
Installation
Installed in a PCIe slot on the motherboard or built-in
LCD monitoring
Hot-swap support
Intuitive alerts
Maintenance
Requires BIOS or software access
Complex operation
Drives not tied to the RAID controller
Easy data recovery
Data Portability
RAID configuration tied to the original card
Difficult to move drives across systems
High compatibility with different OS
Supports various interfaces (IDE/SATA/SCSI)
Compatibility
Varies depending on the brand/driver
Must check version before use