Why NAS drives are different from desktop drives
NAS drives are designed for three things desktop drives are not: continuous 24/7 operation, vibration compensation for adjacent drive vibration in multi-bay enclosures, and error recovery settings tuned for RAID systems. A desktop drive in a 4-bay NAS will work initially — but will likely fail prematurely under continuous workload, and its default error recovery timeout can cause RAID arrays to drop the drive unnecessarily.
CMR vs SMR: always choose CMR
CMR (Conventional Magnetic Recording) writes data in non-overlapping tracks and handles random writes efficiently. SMR (Shingled Magnetic Recording) overlaps tracks for higher density but writes slowly and degrades under heavy random workloads — exactly what NAS systems do. All top NAS drives (WD Red Plus, Seagate IronWolf, Toshiba N300) use CMR. Avoid any NAS drive that doesn't explicitly state CMR.
WD Red Plus vs Seagate IronWolf
The two dominant NAS drive brands. WD Red Plus drives are CMR, rated for 24/7 operation, and come with 3-year warranties. They run at 5,400 RPM (smaller sizes) or 7,200 RPM (10TB+). Seagate IronWolf drives offer similar specs, also CMR, with IronWolf Health Management software for Synology NAS systems. At the same capacity, both are excellent choices — buy whichever has the better price at the time.
How much capacity do you need?
For a home media NAS (movies, photos, backups): 4–8TB per bay is the sweet spot. A 2-bay NAS with 2×4TB in RAID 1 gives you 4TB of protected storage. For a small business or Plex server with large libraries: 8–12TB per bay. Plan for 2–3 years of growth — adding a drive later is more expensive than buying larger now. Our recommendation: buy the largest capacity that fits your budget per bay.