RAID in System Design

RAID (Redundant Array of Independent Disks) is a method used in system design to combine multiple hard drives into one unit for better performance, reliability, or both.

Think of RAID like a team of delivery trucks instead of just one.
Each truck (disk) carries part of the load (data), so:

• Work gets done faster.
• If one truck breaks down, others can still deliver (depending on the RAID type).

Common RAID Types:

1. RAID 0 (Striping)
   🚀 Fast but risky

• Data is split across drives → faster read/write
• ❌ No backup. If one disk fails, all data is lost.

2. RAID 1 (Mirroring)
   🛡️ Safe but uses more space

• Data is copied exactly on two or more drives
• ✅ If one fails, the other has a full copy.

3. RAID 5 (Striping with Parity)
   ⚖️ Balance of speed and safety

• Data and a special backup code (parity) are spread across 3+ drives
• ✅ One disk can fail, and data is still recoverable.

4. RAID 10 (1+0)
   🔥 High speed + high safety

• Combines RAID 1 & 0: mirrored sets, then striped
• 💰 Needs at least 4 drives, expensive but very reliable.

✅ Use in system design:
RAID is widely used in servers, cloud storage, and enterprise systems to ensure data durability and performance.