Mass Storage Technologies
Week 8 · Module 8: Mass Storage Technologies · Download .docx
Objectives
- Compare HDD, SATA SSD, and NVMe SSD speed and use cases
- Explain RAID 0, 1, 5, and 10 configurations
- Identify storage interface connectors and speeds
- Calculate usable capacity for common RAID levels
Key terms
- NVMe
- Non-Volatile Memory Express — PCIe-based SSD protocol up to ~7000 MB/s.
- SATA III
- 6 Gbps interface for HDDs and SATA SSDs (~550 MB/s real-world).
- RAID 0
- Striped — maximum speed, zero redundancy.
- RAID 1
- Mirrored — full copy on second drive, 50% usable capacity.
- IOPS
- Input/Output Operations Per Second — random I/O performance metric.
The concept
Storage spans a wide performance range. A 7200 RPM HDD reads ~150 MB/s sequential. A SATA SSD reaches ~550 MB/s — 3.6x faster. A PCIe 4.0 NVMe SSD hits ~7,000 MB/s — 46x faster than the HDD. RAID adds redundancy (RAID 1, 5, 10) or performance (RAID 0). RAID 5 is a common small-business sweet spot: 3+ drives, distributed parity, survives one failure, and better capacity efficiency than RAID 10. IOPS counts random operations per second — the key metric for OS boot drives and databases, not sequential video storage.
Worked examples
Common mistakes
- Confusing RAID 1 usable capacity — it is always 50% of total raw.
- Treating RAID as a backup — RAID protects against drive failure only, not ransomware or accidental deletion.
- Installing an NVMe SSD in an M.2 SATA-only slot — the drive is not detected.
Self-check
Try each one before you look. A miss here costs nothing and tells you exactly what to reread.
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