This guide explains RAID configurations available for servers with multiple drives, their benefits, and requirements.
What is RAID?
RAID (Redundant Array of Independent Disks) is a method of combining multiple physical drives into one logical unit for improved performance, redundancy, or both. RAID can be implemented via:
- Hardware RAID: Managed by a dedicated RAID controller.
- Software RAID: Managed by the operating system.
Recommended RAID Levels
For servers storing critical data, we recommend:
- RAID 1 for redundancy.
- RAID 10 for redundancy and performance.
RAID Options Overview
| Name | Description | Requisites |
|---|---|---|
| RAID 0 | Stripes data across drives for speed. No redundancy. | 2 or more drives |
| RAID 1 | Mirrors data from one drive to another for safety. | 2 drives of equal size |
| RAID 5 | Stripes data with parity for fault tolerance. | 3 or more drives of equal size |
| RAID 10 | Combines RAID 1 and RAID 0 for speed + redundancy. | 4 or more drives of equal size |
Pros and Cons of Each RAID Level
- RAID 0
- ✅ High performance.
- ❌ No fault tolerance—data loss if one drive fails.
- RAID 1
- ✅ Excellent redundancy.
- ❌ Storage capacity is halved.
- RAID 5
- ✅ Good balance of speed and redundancy.
- ❌ Rebuild times can be long after a failure.
- RAID 10
- ✅ Best mix of performance and redundancy.
- ❌ Requires more drives (higher cost).
Best Practices
- Always use drives of equal size and speed for optimal performance.
- For hardware RAID, ensure the RAID controller has a battery-backed cache.
- Regularly monitor RAID health and configure alerts for drive failures.
- Maintain offsite backups, RAID is not a substitute for backup.
