Fondly referred to as “spinning rust” among some computer nerds, mechanical hard drives seem almost quaint compared to hyper-fast SSDs. Yet, the idea that mechanical hard drives are ready for the trash pile may be more than a little premature.
Mechanical Drives Are Still Getting Faster
Most of you reading this probably have experienced mid-range hard drives that spin between 5400 and 7200 RPM, with transfer speeds between 100-120 Megabytes per second. However, that’s not nearly as fast as hard drives can go.
Higher-end drives easily exceed 200 MB/s when it comes to sequential read and write speeds. 10,000 RPM mechanical hard drives often have sustained transfer rates around the 250 MB/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 doesn’t seem engineers and scientists have reached the limit of HDD technology either. Seagate’s MACH.2 technology essentially stuffs two hard drives into one unit, offering speeds up to 524 MB/s for sustained sequential transfers. If you know anything about SATA III SSDs, you’ll know that this is pretty close to the top speeds possible using a SATA interface.
These MACH.2 drives also come in massive capacities, such as 14TB, at a much lower price per Gigabyte than a comparable SSD. Arrange MACH.2 drives into a suitable RAID array, and you can see speeds measured in gigabytes per second, competing with M.2 SSD performance but at a better per-gigabyte price.
Hard Drives Keep Getting Bigger
The largest M.2 SSD you can buy as we write this comes in at 8TB. That’s more space than most people need, but it’s a far cry from how much space the largest hard drives offer. Of course, we’re talking about the capacities of single-drive units that anyone can buy off the shelf. There are massive SSD volumes in data centers, just as there are massive mechanical drive arrays, but here we’re talking about storage solutions that you might actually order from Amazon for personal use.
In May of 2022, Western Digital announced 26TB hard drives. Seagate announced 30TB drives slated for 2023, and 50TB+ drives slated for 2026. Seagate’s technology roadmap puts a target on 120TB drives alongside the multi-actuator technology that makes MACH.2 drives so fast.
While we expect SSDs to become much cheaper per gigabyte over time, as they’ve already done, it may be quite some time before they overtake mechanical drives in terms of cost-per-gigabyte!
Hard Drives Are the Best Mass Storage Solution
Some types of media don’t benefit from the speed or other side-benefits of going solid state. Backups, media files, and anything that isn’t an application or application data that needs to be streamed to RAM are suitable for storage on a mechanical drive.
SSDs might be worse for long-term cold data storage than mechanical drives, although even hard drives suffer from “bit rot.” Recovering data from a mechanical disk platter in a failed drive may be possible when a failed SSD is unreadable.
Most importantly, as long as the speed limitations of the mechanical drive aren’t an issue, hard drives still rule the roost when it comes to cost-per-gigabyte for online storage. By “online” we mean connected storage you can access as you need it, as opposed to tape drive backup or optical disc backups, which might be cheaper but less convenient.
Hybrid Drives Have Their Place
Somewhat 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 pre-loads data you use frequently or are likely to use next and keeps it ready in the SSD segment of the device.
By combining a small amount of solid-state storage with a large mechanical drive, it’s possible to improve the drive’s performance while keeping its costs down. We expect hybrid drive technology to further extend how relevant mechanical drives are in data centers and some personal computers.
Mechanical Drives Are Here To Stay (For Now)
While “spinning rust” drives might feel like yesterday’s technology, it’s actually a technology that’s being pushed forward with plenty more to offer in the future. The main place we’ve seen such drives disappear are in mobile devices such as laptops. After all, a major weakness of mechanical drives is impact damage, which makes SSDs perfect for a tablet, laptop, or smartphone.
In desktop computers which (hopefully) don’t experience any physical impacts, a large mechanical mass storage drive is still an incredibly valuable resource. Retrieving data from a mechanical hard drive is still much faster than downloading it from cloud storage, after all.