Shingled magnetic recording (often abbreviated as SMR) is a technique used to increase the areal density of a hard drive, allowing manufacturers to store more data on each square inch of the discs (or platters).
The word “shingled” provides a basic overview of how this technique works. On a conventional hard drive, data is stored on parallel magnetic tracks. Those tracks don’t overlap in any way. This is known as perpendicular magnetic recording (PMR).
SMR hard drives overlap tracks slightly, creating “shingles” that result in narrower tracks (and therefore, greater areal density). For applications that require large-scale storage — for instance, certain RAID arrays and cloud storage servers — SMR drives provide excellent storage density at a low overall price.
Advantages and Disadvantages of SMR Hard Drives
As discussed above, SMR drives overlap the magnetic tracks that store data. Sometimes, this means that the hard drive overwrites data in the process. If a track is overwritten, the SMR hard drive will need to rewrite the data from the lost track, which can make the write process take longer.
This is the major downside of SMR technology. When continuously writing very large files — or writing randomly — SMR hard drives are substantially slower than PMR drives.
This downside can be mitigated through effective data management. Data management can be performed in three ways:
- Device-managed SMR drives feature specialized disk controllers that handle the rewriting of overwritten data. Because device management allows drives to be used in different systems interchangeably, this is the most common application of SMR.
- Host-managed SMR drives require a special protocol to write data.
- Host-aware combines drive- and host-managed protocols, optimizing the overall speed of the transfer.
Each technique carries different advantages, but even with well-optimized host-aware data management, SMR drives are slower than PMR drives with identical components. This can be especially problematic if the hard drive is used in a RAID environment, as the “shingling” may lead to data parity errors.
However, the benefits of SMR drives are also notable. An SMR drive can store a tremendous amount of data without requiring significantly more energy than a conventional PCR drive. In some applications, the lower write speeds of PCR drives aren’t a serious concern — for example, if the drive is used for backups or archives, minor differences in write speed aren’t a serious factor.
How do I know whether I have an SMR hard drive?
If you’re buying a new hard drive, the specification sheet will list whether or not the drive uses SMR technology. This wasn’t always the case — but as of 2022, specification sheets will have this information.
To determine whether an older hard drive uses SMR, you can either do some quick research on the drive’s model number or determine whether the drive supports the TRIM command. Most solid-state drives (SSDs) and many SMR hard drives support the TRIM command, but PCR drives do not.
Here’s a guide from HowToGeek for determining whether TRIM is enabled in Windows. However, note that SMR drives don’t always use TRIM — the safest way to determine whether your drive uses SMR is to search for the model number.
Does SMR technology make hard drive data recovery more difficult?
Shingled magnetic recording can complicate data recovery in some circumstances. If the drive supports the TRIM command, deleted data is usually unrecoverable (we still provide free evaluations and a no data, no charge guarantee, enabling our customers to attempt recovery on deleted files regardless of the circumstances).
Data corruption may also become an issue, depending on the nature of the failure. However, most standard data recovery scenarios — such as failed read/write heads, locked spindles, and other physical media failures — have high chances of a successful case result.
Need to recover data from an SMR hard drive? We’re here to help. As the worldwide leaders in hard drive recovery, Datarecovery.com invests heavily in research and development. Each of our fully equipped laboratories has the capabilities to recover SMR hard drives, along with conventional PMR hard drives, solid-state drives, RAID arrays, and other storage devices.
Fill out our online case form to get started or call 1-800-237-4200 to discuss data recovery with an expert.