Disk drives are easy to ignore: one can assume they keep getting bigger and faster and factor that in whenever buying servers or arrays, without having to care much about what’s inside.
But Seagate is about to change that by adding a second actuator to its drives.
The actuator is the device that moves a hard disk’s arm so that its read/write heads go to the spot on a disk where it needs to find or deposit data. Disks contain multiple platters and there’s one arm for each platter, but the actuator moves all of them at once. So even though the typical time an actuator requires to move an arm into position is about 20 milliseconds, actuator movements are a bit of a bottleneck for storage.
Which is why Seagate has cooked up a drive with two actuators. Each actuator will still drive its own squad of arms, but each will also only have half of a disk drive’s platters to worry about.
The result will be a bit like a needle on each side of a record, with a different track playing from each side.
While that would produce discordant music, the two actuators will work in parallel and Seagate has already demonstrated 480MB/s throughput. That's faster than it’s achieved with its speediest current conventional hard disks (although solid state storage is way faster).
The drives won’t need custom hardware because they’ll employ standard connectors and can use protocols like SAS or NvME to talk to servers. The drives will, however, present to an operating system or hypervisor as two discrete drives. Applications will therefore have the option to devote each actuator to different tasks. Imagine, therefore, a drive that has transactional data in one part of its innards, archive data in the other, and uses auto-tiering software to move data between its two halves!
Seagate hopes this technology, which it calls MACH.2, will result in conventional hard disk that delivers performance better than single-actuator drives and offers a new tier of storage between hard disks and more expensive and lower-capacity solid-state disks.
MACH.2 will debut in 2019. Seagate plans to eventually add “HAMR” technology that it will use to propel hard disks to 20 terabytes and beyond, starting in the year 2020.
All of which means that in a year or two, we’ll have disks with colossal capacity, faster throughput and new ways to control their behaviour. Which might make them just a little harder to ignore.
Seagate schlepped Simon Sharwood to Singapore for a press event.