# HDDs in 2026: CMR vs SMR, and what Windows can still do with spinning disks

> Where hard drives still make sense on Windows, how SMR changes write behaviour, and how storage pools and ReFS fit in.

**Tested on**

- Build: 26100.33650
- Edition: Pro (26H2) / Server
- Architecture: x64
- Evidence: E1
- Verified: 2026-10-29

## The short answer

Hard drives lost the system-disk role and kept three jobs:

1. **Bulk cold storage** — media, archives, backups.
2. **Cheap capacity for a NAS or storage pool**.
3. **Sequential workloads** where cost per TB dominates.

They are bad at random I/O and at anything interactive. On Windows, an HDD as the boot drive is the single biggest perceived-speed downgrade you can choose in 2026.

## CMR vs SMR, in one paragraph

- **CMR** (conventional magnetic recording) writes tracks side by side. Predictable performance.
- **SMR** (shingled) overlaps tracks to fit more data per platter. Writes that land inside an already-written band require **read-modify-write** of a whole band, so sustained random writes collapse.

SMR is fine for append-only archives and bad for RAID rebuilds, VM images and active databases. Many consumer drives are SMR without a prominent label; the manufacturer's datasheet is the only reliable source.

| Workload | CMR | SMR |
|---|---|---|
| Media archive (write once) | Good | Good |
| Backup target, sequential | Good | Acceptable |
| VM disk images | Good | Poor |
| RAID rebuild | Acceptable | Painful |
| Game installs / unpacking | Acceptable | Poor |

## What Windows does with them

- **Storage Spaces** can pool drives and add redundancy or thin provisioning — see [Storage Spaces](https://winbook.fyi/en/hardware/storage/storage-spaces/).
- **ReFS** adds integrity streams and block cloning on supported volumes; it is not a boot filesystem for client Windows.
- **NTFS** remains the default and is fine for a single drive.
- **Windows Backup / third-party tools** handle the backup role; the drive itself does not care.

```powershell
Get-PhysicalDisk | Select-Object FriendlyName,MediaType,BusType,Size,HealthStatus,SpindleSpeed
Get-Volume | Select-Object DriveLetter,FileSystemType,Size,SizeRemaining
```

`MediaType` reports `HDD` vs `SSD`, which is enough for pool planning, but not for CMR/SMR — that has to come from the datasheet.

## Where an HDD still wins

- **Cost per TB** at 8TB and above.
- **Write endurance** for surveillance/archive patterns.
- **Cold data** that would waste SSD endurance and money.

Where it loses: anything with random reads (app launch, VM boot, indexing, Windows Update on many small files).

## A sane Windows layout

| Role | Media |
|---|---|
| Boot + apps | NVMe SSD (DRAM or HMB) |
| Projects/VM images | NVMe or SATA SSD |
| Media/archive | HDD, CMR preferred |
| Backup target | HDD or NAS, separate from the source |
| Scratch/temp | SSD (HDD scratch is painful) |

> **Tip: Buy the datasheet, not the marketing name**
>
> "NAS drive", "surveillance drive" and "desktop drive" describe firmware tuning and workload ratings, not recording technology. Check the datasheet for CMR/SMR and for the workload rating (TB/year) before putting a drive in a RAID or a 24/7 box.

## Verify before you trust a pool

1. Confirm every drive reports `Healthy` before adding data.
2. Fill the pool to ~80% and re-test write speed — SMR and shingled caches fail late, not early.
3. Run a scrub/verify job if the pool supports it.
4. Keep a backup: a redundant pool protects against drive failure, not deletion, ransomware or controller failure.

## Related

- [NVMe generations](https://winbook.fyi/en/hardware/storage/nvme-generations/)
- [Storage Spaces](https://winbook.fyi/en/hardware/storage/storage-spaces/)
- [Drive health](https://winbook.fyi/en/hardware/storage/health-smart/)

## Lab boundary

E1. Recording technology is a drive property documented by the manufacturer; Windows reports `MediaType` but not CMR/SMR. No physical HDD was tested for this page.

## Sources

- [Microsoft Learn — Storage Spaces overview](https://learn.microsoft.com/en-us/windows-server/storage/storage-spaces/overview)
- [Microsoft Learn — NTFS overview](https://learn.microsoft.com/en-us/windows-server/storage/file-server/ntfs-overview)
- [Microsoft Learn — Get-PhysicalDisk](https://learn.microsoft.com/en-us/powershell/module/storage/get-physicaldisk)

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Source: https://winbook.fyi/en/hardware/storage/hdd-cmr-smr/