Can SMR drives be used in RAID?
Technically yes, but you should not. SMR drives' write speed collapses under the sustained writes of a RAID rebuild, which can make rebuilds take days or stall entirely: the moment you most need reliability. For any RAID array, use CMR drives. SMR is fine only for single-drive, write-light, archival use.
Last verified July 22, 2026 · 2 official sources checked Updated
As an Amazon Associate we earn from qualifying purchases on Amazon.ca.
An SMR drive will function in a RAID array day to day, so the honest answer is "it can be done", but it is a genuinely bad idea, and the reason is the rebuild.
Why SMR and RAID clash
SMR (shingled magnetic recording) overlaps write tracks like roof tiles to pack in more capacity. The trade-off is that changing data means rewriting whole overlapping zones, so sustained random and heavy sequential writes slow to a crawl. A RAID rebuild is exactly that: hours of continuous writes to reconstruct the array. On an SMR drive the rebuild can drop to a trickle, taking days or stalling, and while it stalls, a single-parity array has no fault tolerance. That is the worst possible time for a drive to misbehave.
When SMR is fine
SMR drives are perfectly good for single-drive, write-once, read-many uses: an external backup drive, an archive you fill slowly, cold storage. It is the sustained-write RAID rebuild that exposes them.
The rule
For any NAS RAID array (SHR, RAID 5, RAID 6, RAID 10) use CMR drives. NAS lines (IronWolf, WD Red Plus/Pro, Toshiba N300) and enterprise drives (Exos, Ultrastar) are all CMR. The table is filtered to CMR only.
Drives that solve this
Live Amazon.ca prices in CAD, ranked by price per terabyte. The Recording column is verified against manufacturer documentation. Prices checked
| Model | Capacity | Recording | Price | CA$/raw TB | |
|---|---|---|---|---|---|
 Seagate Exos X22 22TB SATA 6Gb/s 7200RPM 3.5" Enterprise Hard Drive - ST22000NM001ENewbest price per TB CMR recording, SATA enterprise drive Amazon.ca · sold by ServerPartDeals · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,108Buy on Amazon | 22 TB | CMR ✓ | CA$1,108 | CA$50.38/TB | Buy on Amazon |
 Seagate IronWolf Pro 32TB Enterprise NAS Internal HDD Hard Drive – CMR 3.5 Inch SATA 6Gb/s 7200 RPM 512MB Cache for RAID Network Attached Storage, Rescue Services (ST32000NTZ00)New CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by THEKEYKEY · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,740Buy on Amazon | 32 TB | CMR ✓ | CA$1,740 | CA$54.37/TB | Buy on Amazon |
 Seagate Exos M 28TB Enterprise Internal Hard Drive HDD - 3.5in 6GB/s SATA 7200RPM 2.5M MTBF (ST28000NM003K)New CMR recording, SATA enterprise drive Amazon.ca · sold by Amazon.ca · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,543Buy on Amazon | 28 TB | CMR ✓ | CA$1,543 | CA$55.11/TB | Buy on Amazon |
 Seagate IronWolf 10TB NAS Internal Hard Drive HDD – CMR 3.5 Inch SATA 6Gb/s 7200 RPM 256MB Cache for RAID Network Attached Storage (ST10000VN0008) (ST10000VNZ008/N0008)New CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Deals2You · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$579Buy on Amazon | 10 TB | CMR ✓ | CA$579 | CA$57.91/TB | Buy on Amazon |
 Seagate Exos X24 ST20000NM002H 20TBNew CMR recording, SATA enterprise drive Amazon.ca · sold by THEKEYKEY · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,165Buy on Amazon | 20 TB | CMR ✓ | CA$1,165 | CA$58.25/TB | Buy on Amazon |
 Western Digital HUH721212ALE604 12TB Ultrastar DC HC520 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 256MB Cache, 3.5"New CMR recording, SATA enterprise drive Amazon.ca · sold by Seller_King · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$699Buy on Amazon | 12 TB | CMR ✓ | CA$699 | CA$58.25/TB | Buy on Amazon |
 Seagate Exos X24 24TB Enterprise Internal Hard Drive HDD - 6GB/s SATA 7200RPM 2.5M MTBF (ST24000NM002H)New CMR recording, SATA enterprise drive Amazon.ca · sold by THEKEYKEY · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,400Buy on Amazon | 24 TB | CMR ✓ | CA$1,400 | CA$58.33/TB | Buy on Amazon |
 Toshiba N300 PRO 8TB Large-Sized Business NAS (up to 24 Bays) 3.5-Inch Internal Hard Drive - Up to 300 TB/Year Workload Rate CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWG780XZSTBNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by HYPER MEGA Electronics · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$480Buy on Amazon | 8 TB | CMR ✓ | CA$480 | CA$60.00/TB | Buy on Amazon |
 Seagate IronWolf Pro 20TB Enterprise NAS Internal HDD Hard Drive – CMR 3.5 Inch SATA 6Gb/s 7200 RPM 256MB Cache for RAID Network Attached Storage, Rescue Services (ST20000NTZ01/ST20000NT001)New CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by THEKEYKEY · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,235Buy on Amazon | 20 TB | CMR ✓ | CA$1,235 | CA$61.75/TB | Buy on Amazon |
 Western Digital 22TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD221KFGXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Deals2You · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,400Buy on Amazon | 22 TB | CMR ✓ | CA$1,400 | CA$63.64/TB | Buy on Amazon |
Related questions
- Why is my RAID rebuild taking days?
- How do I tell if my hard drive is SMR or CMR?
- Can I mix SMR and CMR drives in a NAS?
- Is the WD Red 4TB SMR or CMR?
- What drive should I buy to replace a failed drive in SHR?
- How long does a Synology RAID rebuild take?
- Can I replace a drive in RAID 5 with a smaller one?
- Is the WD Red 6TB SMR or CMR?
Sources
Every technical claim on this page is checked against manufacturer and standards documentation. Dates are when each source was last reviewed.
- Western Digital: Internal drives CMR/SMR statement (checked 2026-07-22)
- Seagate: CMR/SMR drive list (checked 2026-07-22)