Are mechanical hard drives really obsolete?

Mechanical drives are no longer the best option for running operating systems and applications, but these devices have many advantages in their own right and continue to improve with new technological advances.

Affectionately known as “spinning rust” among some computer nerds, mechanical hard drives look almost quaint in comparison to hyper-fast SSDs. However, the idea that mechanical hard drives are ready for the trash can be more than premature.

Mechanical units are still faster

Most of you reading this have probably experienced mid-range hard drives that spin between 5400 and 7200 RPM, with transfer speeds of between 100 and 120 megabytes per second. However, that’s not as fast as hard drives can go.

High-end drives easily top 200MB/s when it comes to sequential read and write speeds. 10,000 RPM mechanical hard drives often have sustained transfer rates around the 250MB/s mark. While this is still much slower than an SSD, it’s still fast enough for many applications and uses.

Best of all, it seems that engineers and scientists haven’t reached the limit of HDD technology either. Seagate’s MACH.2 technology essentially crams two hard drives into one drive, offering speeds of up to 524MB/s for sustained sequential transfers. If you know anything about SATA III SSDs, you’ll know that it comes pretty close to the maximum speeds possible with a SATA interface.

These MACH.2 drives also come in massive capacities, like 14TB, at a much lower price per Gigabyte than a comparable SSD. Arrange MACH.2 drives in a proper RAID array and you can see speeds measured in gigabytes per second, rivaling the performance of M.2 SSDs but at a better price per gigabyte.

Obviously, there are many other benefits that SSDs offer beyond speed, but for data centers, media servers, and many other use cases, mechanical drives will be attractive for many years to come.

Hard drives keep growing

The largest M.2 SSD you can buy as we write this is 8TB. That’s more space than most people need, but it’s a far cry from the amount of space offered by the largest hard drives. Of course, we are talking about the capacities of single disk drives that anyone can buy on the market. There are massive volumes of SSDs in data centers, just like there are massive mechanical drive arrays, but we’re talking about storage solutions here that you could actually order from Amazon for personal use.

In May 2022, Western Digital announced 26TB hard drives. Seagate announced 30TB drives slated for 2023 and 50+TB drives slated for 2026. Seagate’s technology roadmap targets 120TB drives along with the multi-actuator technology that makes MACH.2 drives be so fast

While we expect SSDs to get much cheaper per gigabyte over time, as they already have, it may be quite some time before they surpass mechanical drives in terms of cost per gigabyte!

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Hard drives are the best mass storage solution

Some types of media do not benefit from the speed or other secondary benefits of going solid state. Backups, media files, and anything other than app or app data that needs to be streamed to RAM are all suitable for storage on a mechanical drive.

SSDs can be worse for long-term cold data storage than mechanical drives, though even hard drives suffer from “bit rot.” Data recovery from a mechanical drive platter to a failed drive may be possible when a failed SSD is unreadable.

Most importantly, as long as mechanical drive speed limitations are not an issue, hard drives will continue to dominate the cost per gigabyte of online storage. By “online” we mean attached storage that you can access when you need it, as opposed to backing up to tape drives or backing up to optical discs, which can be cheaper but less convenient.

Hybrid drives have their place

Ironically, mechanical hard drives have also benefited from SSD technology in the form of “hybrid” hard drives. These drives contain a small amount of fast flash memory that acts as a data cache. The firmware in the drive intelligently preloads the data you use frequently or will likely use next and keeps it ready on the device’s SSD segment.

By combining a small amount of solid-state storage with a large mechanical drive, you can improve drive performance while keeping costs down. We expect hybrid drive technology to further expand the relevance of mechanical drives in data centers and some personal computers.

Mechanical drives are here to stay (for now)

While “spinning rust” drives may seem like the technology of the past, it is actually a technology that is being pushed forward with much more to offer in the future. The main place we’ve seen such drives disappear is on mobile devices like laptops. After all, one of the main weaknesses of mechanical drives is impact damage, which makes SSDs perfect for a tablet, laptop, or smartphone.

External mechanical drives can be safely stored while powered off in a laptop bag, so while mechanical drives are no longer popular inside mobile devices, they are never far behind.

On desktop computers that (hopefully) don’t experience any physical shock, a large mechanical mass storage drive is still an incredibly valuable resource. After all, recovering data from a mechanical hard drive is still much faster than downloading it from cloud storage.