Every drive tracked here is listed with its recording technology. CMR is safe for RAID, ZFS, and NAS; SMR is not. We currently track 163 CMR drives, 0 SMR, and 0 unverified. Search your exact model below to check it.
Filter by recording technology and search your exact model — this is the "is my drive CMR?" lookup. CMR drives are safe for arrays; the list defaults to CMR, in-stock. Out-of-stock drives show "Check availability" rather than a price, and are never ranked on $/TB.
Conventional Magnetic Recording writes data tracks side by side on the platter without overlapping them. Because each track stands alone, the drive can rewrite any single track without disturbing its neighbours, which gives CMR its defining property: predictable, consistent random-write performance under any workload. Every enterprise nearline drive and every NAS-rated drive uses CMR (or ePMR, an enhanced but still conventional, non-shingled variant), because datacenter and array workloads cannot tolerate the write penalties of shingling. When you buy an enterprise Exos, Ultrastar, or a NAS IronWolf or Red Plus, you are buying CMR by design.
Shingled Magnetic Recording overlaps adjacent tracks like the shingles on a roof, packing more capacity onto the same platter. The catch is that overlapping tracks cannot be rewritten independently: changing data on one track forces the drive to read and rewrite every track in the overlapping band. This is write amplification, and it is where SMR's problems begin.
Under the sustained random-write load of a RAID rebuild or a ZFS resilver, that amplification is catastrophic. Rebuilds that should take hours stretch into days — dangerously extending the window during which a second drive failure would destroy the entire array. ZFS resilvers can slow to a crawl or fail to complete at all. Drives can even drop out of an array under load when the controller times out waiting for the drive to finish its internal rewrites. This is why SMR is disqualifying for RAID and ZFS: it is not a performance preference you can tune around, it is a reliability failure mode. For any array, CMR only.
To verify a drive you already own or are about to buy, look up its exact model number — the full part number, not the marketing family name, since recording technology varies within a family. The manufacturer's spec sheet lists the recording method definitively. If you cannot find documentation, there is a behavioural tell: write a large file (bigger than the drive's CMR cache, typically tens of gigabytes) and watch the sustained write speed. A CMR drive holds a steady rate; an SMR drive's throughput collapses once the cache fills and it must start shingling in place. The searchable list above already carries the recording method for every model we track.
The most notorious incident is the 2020 WD Red controversy. WD shipped SMR in some plain WD Red (non-Plus) drives without disclosing it, and ZFS users discovered the problem the hard way when resilvers failed. WD's resolution clarified the lineup: WD Red Plus and WD Red Pro are CMR, while plain WD Red at some capacities is SMR. Seagate has similarly shipped SMR in some Barracuda desktop drives at several capacities. We state these facts as documented by the manufacturers and the community reporting at the time, and we deliberately do not assert specific capacities we have not verified on a current spec sheet or in our own database — recording technology can change between revisions, so always confirm the exact model before you buy.
For NAS and RAID, use CMR only — no exceptions. See the NAS HDD tracker, the TrueNAS picks, and the Plex server guide, all of which are CMR-focused. For a single-drive backup or archive target where writes are sequential and there is no array to rebuild, SMR is acceptable and its extra capacity per dollar can even be an advantage. The distinction is entirely about whether the drive lives in an array: in an array, shingling is a liability; standing alone doing sequential writes, it is fine.
Glossary · NAS HDD · TrueNAS drives · Plex drives · SATA HDD · Refurbished enterprise
Look up the exact model number — not the marketing family name — on the manufacturer's spec sheet, which lists the recording technology. On this page, every tracked drive is labeled with its recording method, so you can search your model directly. A behavioural tell also works: SMR drives show sustained write speed collapsing once their CMR cache fills during a long write, while CMR drives hold a steady rate.
For RAID, ZFS, and NAS use, CMR is unambiguously better — it delivers predictable random-write performance and rebuilds reliably. SMR trades that away for slightly higher capacity per platter, which only makes sense for single-drive, mostly-sequential workloads like an archive or a backup target. For any array, CMR is the correct and safe choice.
SMR overlaps data tracks like roof shingles, so rewriting one track forces the drive to rewrite the whole overlapping band — massive write amplification. Under the sustained random writes of a RAID rebuild or ZFS resilver, that causes rebuilds to take days instead of hours (extending the window in which a second failure destroys the array), resilvers that may never complete, and drives dropping out of the array under load. It is a reliability problem, not a performance preference.
In 2020 WD was found to have shipped SMR in some plain WD Red (non-Plus) drives at certain capacities without disclosure, which caused ZFS resilver failures and a community backlash. WD's resolution: WD Red Plus and WD Red Pro are CMR across the line, while plain WD Red at some capacities remained SMR. Always verify the exact model number against WD's current spec sheet rather than trusting the family name.
Effectively yes. Every enterprise nearline and datacenter drive family — Seagate Exos, WD Ultrastar, Toshiba MG — uses CMR (or ePMR, a conventional non-shingled variant), because datacenter workloads demand predictable performance. This is a major reason refurbished enterprise drives are a safe RAID choice: they are CMR by design. Every enterprise HDD tracked here is CMR/ePMR.
Yes — single-drive backup and archive is the one use case where SMR is acceptable, because those workloads are largely sequential writes that avoid SMR's worst-case rewrite penalty. Just never place an SMR drive in a RAID array, ZFS pool, or NAS parity role. Keep SMR to standalone, sequential, cold-storage duty.
Severely. ZFS resilver and scrub operations generate exactly the sustained random-write pattern that triggers SMR's worst-case behaviour, and SMR drives can make a resilver crawl for days or fail to complete, putting the pool at risk. The 2020 WD Red incident surfaced precisely because ZFS users hit resilver failures. Use CMR-only in any ZFS vdev.
No — they are orthogonal. HAMR (Heat-Assisted Magnetic Recording) is a method for writing bits more densely by briefly heating the platter, and it can be used with conventional non-shingled tracks. SMR (Shingled Magnetic Recording) is about overlapping tracks regardless of how each bit is written. A HAMR drive is not inherently SMR, and current high-capacity HAMR enterprise drives are CMR-class for RAID purposes.