Seagate finds sets of two heads are cheaper than one in its new and very fast MACH.2 dual-actuator hard disks
- Reference: 1622786291
- News link: https://www.theregister.co.uk/2021/06/04/seagate_mach_2_lproduction_costs/
- Source link:
MACH.2 gets its speed by using two actuators – the twitchy little devices that move the arms carrying read/write heads to the parts of a disk’s platter that matter. While disks contain multiple platters and heads, they move all their arms at once and can only do one thing at a time with one arm. MACH.2 drives have two actuators, each driving arms and heads that address half of the platters in a disk and can do two things at once. They’re therefore pleasingly rapid.
MACH.2 also offer pleasingly large capacities up to 20TB. That combination of speed and capacity has seen Microsoft buy up plenty of the Seagate’s early production run and [1]put them to work in the [2]Project Olympus servers it deploys inside the Azure cloud
[3]
But MACH.2 is not yet a product the rest of us can go out and buy.
[4]US-based hard disk drive suppliers face further scrutiny over whether they've shipped proscribed HDDs to Huawei
[5]To have one floppy failure is unlucky. To have 20 implies evil magic or a very silly user
[6]Cisco discloses self-sabotaging SSD bug that causes rolling outages for some Firepower appliances
[7]China cracks down on web infomercials, which means more compliance chores for Alibaba
A recently surfaced transcript of a Seagate investor day, sighted by The Register , quotes senior veep Jeff Fochtman as saying MACH.2 is “really still in a technology-staging mode”. Despite that status the drives have a dozen customers and Seagate is ramping up production.
Fochtman said that once MACH.2 hits 30TB it will offer an irresistible proposition “in many large datacenter environments.”
[8]
He also dropped this nugget:
A notable benefit to dual actuator technology standardization is that it drastically cuts down test time, and therefore, hard drive production time is greatly reduced. This is a benefit we're looking forward to recognizing on the cost side of the business.
When a vendor has a clear technology advantage, they charge a premium because they can and because they have a duty to shareholders. Hence Fochtman saying Seagate intends to essentially bank the cost benefits MACH.2 delivers.
But once competition kicks in, prices usually fall. And when that happens, it will prove that two heads – or actuators – are better than one. ®
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[1] https://blog.seagate.com/enterprises/microsoft-nearly-doubles-iops-seagate-exos-mach2-dual-actuator/
[2] https://www.theregister.com/2016/11/01/microsoft_tries_to_reboot_open_hardware_innovation/
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/storage&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YLn5wWAYieiRxuthNHlTugAAAMU&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[4] https://www.theregister.com/2021/05/12/us_hdd_export_probe/
[5] https://www.theregister.com/2021/04/16/on_call/
[6] https://www.theregister.com/2021/05/20/cisco_firepower_ssd_bug/
[7] https://www.theregister.com/2021/04/26/china_livestreaming_rules/
[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/storage&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YLn5wWAYieiRxuthNHlTugAAAMU&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[9] https://whitepapers.theregister.com/
Re: Is this new?
I searched for a link couldn't find it. Can you?
WD has been developing 2-actuator in competition with Seagate since at least 2019:
"Western Digital to Demo Dual-Actuator HDDs Next Week: Double the Actuators for Double the Perf", Anandtech, March 2019.
I was wondering why moving from "1" to "2" took so long, or what else was involved that made that step suddenly worthwhile. Read "Tom's hardware" analysis, it seems that "As hard drive capacity grew further ... random read/write IOPS-per-TB performance dropped beyond comfortable levels for data centers".
So 2 actuators allows for higher capacity drives without sacrificing random read/write IOPS performance.
Here is the relevant section quoted
> Historically, HDD makers focused on capacity and performance: every new generation brought higher capacity and slightly increased performance. When the nearline HDD category emerged a little more than a decade ago, hard drive makers added power consumption to their focus as tens of thousands of HDDs per data center consumed loads of power, and it became an important factor for companies like AWS, Google, and Facebook.
> As hard drive capacity grew further, it turned out that while normal performance increments brought by each new generation were still there, random read/write IOPS-per-TB performance dropped beyond comfortable levels for data centers and their quality-of-service (QoS) requirements. That's when data centers started mitigating HDD random IOPS-per-TB performance with various caching mechanisms and even limiting HDD capacities.
> In a bid to keep hard drives competitive, their manufacturers have to continuously increase capacity, increase or maintain sequential read/write performance, increase or maintain random read/write IOPS-pet-TB performance, and keep power consumption in check. A relatively straightforward way to improve the performance of an HDD is to use more than one actuator with read/write heads, as this can instantly double both sequential and random read/write speeds of a drive.
I remember fixed head disks.
Nothing new.
I remember using disks with one set of heads per track.
Bloody huge though. Seem to remember seeing one that must have been over a metre across.
Re: I remember fixed head disks.
Any day now someone will reinvent drum storage.
Not new
Using ordinary drives in a RAID enclosure can also do that, at least for READ operations. The controller parallelizes read requests, distributing them around the disks, and using whichever disk has the heads in the best place for a particular request, that's been around since the 1980s at least. Looks like the Seagate solution is just to put this in one drive box & call it a single disk.
Reduced testing time
That's absolutely brilliant. The drive runs faster, therefore it can be completely tested faster, therefore production time and cost goes down. Pure genius.
Re: Reduced testing time
Maybe I'm more paranoid about data storage than Seagate. I would have thought that testing the drive would mean testing that arm1 can read what arm0 wrote and all the other three combinations. You might be able to do write0-read0-read1, the write1-read0-read1 but still it means the test takes twice as long a single arm disk.
Or is there no ability for one arm to read the other's data? In which case a 30 TB dual arm drive is really two 15 TB conventional disks jammed into one package in a RAID0 format. If that is the case then the only advantage is space and power saving and no speed advantage.
Re: Reduced testing time
It reads like it's the 2nd one you state. i.e. Two sets of platers, each with their own actuators, sharing the same spindle, case and controller.
Also if it's RAID 0, aka stripe, then you'd be up to doubling the performance, as you can be reading or writing to both sets of platters at the same time. i.e. half the data via 1 actuator, the other half via the other.
Although I'd assume any performance gain is going to be dependent on the structure of your data?
Re: Reduced testing time
Its not raid 0, its presented to the host as 2 drives.
This is, 2 smaller drive in 1 case, with 1 sas and power interface, with 1 spindle, but 2 sets of actuators.
Re: Reduced testing time
The pictures that I saw were 10 platters, and five read/write heads for the top five platters connected, and five read/write heads for the bottom five platters connected. Instead of all ten heads connected. Like having two hands with five fingers each instead of one hand with ten fingers.
It's very significant space and power savings compared to a RAID drive, and speed advantage compared to a single disk drive.
Conner Chinook
[1]This isn't entirely new .
[1] https://en.wikipedia.org/wiki/Conner_Peripherals#Performance_issues_and_the_%22Chinook%22_dual-actuator_drive
Re: Conner Chinook
Chinooks had two heads per surface. A MACH.2 20TB drive is more like 2x ordinary 10TB drives that share an enclosure, motor, controller and power/data connections.
Marketing missed a trick
Surely they should have called it the [1]Zaphod drive, since he had two heads as well
[1] https://en.wikipedia.org/wiki/Zaphod_Beeblebrox
Is this new?
I don't get this. When I had an HP disk storage system to worry about all of the (rather expensive) drives claimed to have dual activators. What's different about these Seagates?