Google Proposes New Hard Drive Format For Data Centers (thestack.com)

An anonymous reader writes: In a new research paper the VP of Infrastructure at Google argues for hard drive manufacturers and data center provisioners to consider revisions to the current 3.5" form-factor in favour of taller, multi-platter form factors — with the possibility of combining the new format with HDDs of smaller circumference which hold less data but have better seek times. Eric Brewer, also a professor at UC Berkeley, writes "The current 3.5" HDD geometry was adopted for historic reasons – its size inherited from the PC floppy disk. An alternative form factor should yield a better TCO overall. Changing the form factor is a long term process that requires a broad discussion, but we believe it should be considered."

Comments

Form Factor not "Format"

[michaelmalak]

Also, I thought the world was going SSD anyway, which is thinner, not thicker?

Re:Form Factor not "Format"

[drinkypoo]

The world will probably keep using spinning rust until purchase price (not TCO) on SSDs is lower. I wouldn't be surprised if makers went back to 5.25 x half height, and low spindle speeds. It would still permit large throughput with high density, but seeks would be slower. Not a big deal with enough caching in front of them, and/or with enough disks in an array. As SSDs approach HDD price, they will take up more of the workloads that actually have to be fast anyway.

Re:Form Factor not "Format"

[p4ul13]

SSD is the heir apparent, but platter based disk storage will likely provide higher capacity at denser, more affordable prices for quite some time to come. I suspect Google is proposing this altered platter HD design as something that could bridge the gap until SSD reaches an affordability / density point that can catch up / replace conventional platter HD designs.

Re:Form Factor not "Format"

[gman003]

That's odd, because my laptop's SSD is four years old and still has plenty of usable life left - and it's from a middle-line vendor, from the early SATA3 days, so it's not even a particularly good SSD. The hard drive in the same laptop (dual-bay) is actually reporting as closer to failure. Maybe that's because it's a laptop, so it suffers more vibration and temperature variation, which is harder on hard drives than solid-state.

And the rest of your bitching seems to be based more on shoddy cloud hosts than SSDs, or on badly-configured servers. "SSDs are too fast, they bring down the entire system by filling up RAM"... wouldn't that be true of hard drives as well, IF they could transfer data that quickly?

Re:Form Factor not "Format"

[Anonymous Coward]

Old SSDs died quickly under DB loads - not enough write count in their lifetime. New ones are better, but still won't last as long as HDD.

Let's take a decent 15k, even ignoring seek times the rotational latency limits us to about 500 IOPS.
Saturating that with 4k writes 24/7 for a year... about 63.12 TB written.
What's the write rating on a 200GB intel DC P3700? 3737.6TB.
Do you honestly expect that HD to survive for nearly 60 years?

Re:Form Factor not "Format"

[Dutch Gun]

You could very well be right. Speaking of oddball heights, the first 500 *MB* drive I bought (back when the main network drive was 120MB) cost $1000, and it was actually a 3 1/2" double-height size, meaning the bay next to it had to be clear before I could install it. It wasn't a problem since I was simply installing it in a workstation. This obviously wouldn't work for Google, since I'm certain they use computers with front-mounted hot-swappable 3 1/2" drive bays all neatly packed together - I've seen how nicely these work with my Synology 5-bay NAS. Unless a new form factor becomes standardized, you can't really hack in a solution... at least not on the scale Google is dealing with.

I don't think Google is going to get its way here with a new standardized size, at least at mass adoption scales. Inertia is pretty damn hard to overcome, even if potentially superior solutions exist. I mean, the US is still using imperial measurements, for heaven's sake. The fact that we measure them as 3 1/2" inch drives should tell you something about how hard it is to change standards.

Re:Too late?

[JoeMerchant]

I just wonder if, by the time they agree on this (if they do) the price of SSDs will have dropped enough so that they can be used instead? Storage-wise they are already there, and then some.

The point is to keep spinning platters cost-competitive with SSDs - a taller, smaller form factor would increase performance and reduce TCO... I'm thinking they're looking at something like lots of 1.8" platters stacked 4" high, they can spin faster, have faster seek times, and package multiple TB per unit, and I think the longer single bearing should be a more favorable geometry than the ultra-thin notebook compatible drives that have been developed for the last 10 years. It will be slower than SSD, but the power performance (which is the key to TCO) should remain competitive with SSDs for a long time to come. Also, presumably, if this takes off it would be datacenter focused, so longevity (again, TCO focus) should also be "baked into" the design in favor of lower retail price.

Multiple heads

[chriswaco]

Multiple heads on each side of the platter might be a better solution, one for the inner part and one for the outer.

Re:Multiple heads

[Andrew Lindh]

This has been done before.... Both outside/middle dual heads and dual independent actuators on each side. Multi heads can increase performance, but cost space, power, and money. Also more parts = lower MTBF. They don't increase storage density. If you want performance use SSD.

http://www.tomshardware.com/ne...

Re:Multiple heads

[nojayuk]

There were SCSI drives with four head actuators, one in each corner of the drive casing. They were treated as four separate drives logically and used to speed up reads on a "first to deliver the requested block" basis. They were horrendously expensive and it turned out to be very difficult to optimise the read process to gain the desired perfomance boost.

Re:Go for it! Bring back full height 5 1/4" drives

[mrchaotica]

Multi-platter was always a good idea, I assume it stopped in a desperate attempt to cut costs.

Wait, what? Last time I opened up a dead 3.5" hard drive (which was only a few years ago) it had either three or four platters. Are you saying they typically only have one now?

But yes, I agree that if they want taller drives, 5 1/4" full height would be a good form factor. Maybe even not with 5" platters! If they want quicker speeds, they could maybe put four separate spindles of the platters from 2.5" drives inside the same box.

2.5" 4X drives

[wren337]

Surprised they haven't just gone with 2X or 4X height 2.5" drives. Same connectors, same platters, easy retrofit. You just need a different bracket.

Re:Go for it! Bring back full height 5 1/4" drives

[jeffb (2.718)]

It sounds like you think that manufacturers have stopped making multi-platter drives. That's not true. Seagate and WD both use seven platters in their highest-capacity (10TB, standard-height) drives. The linked article further states that they use seven platters "instead of the usual six".

I don't know how prevalent single-platter drives are today, but multi-platter drives certainly haven't disappeared.

Re:Eric Brewer = Moron

[yodleboy]

Could be that Google has some inside information that leads them to believe that prices on SSD will not be dropping to acceptable levels any time soon, despite what SSD boosters would have us all believe. If they are proposing something like this, they must have some inkling that spinning platters have a great deal of life left.

Horse sense

[TheRealHocusLocus]

The current 3.5" HDD geometry was adopted for historic reasons --- its size inherited from the PC floppy disk.

The form factor of 3.5" floppy drives was decided during the early planning stage of the Great Data Railroad. You can place exactly 16 3.54" (90mm) bare floppy discs side by side within the standard railroad gauge of 4 feet 8.5 inches. For the original 1982 HP single sided format of ~280kB this yields roughly ~4.3mB along every 3.5" of railroad track, or 137 rows along the floor of a a standard 40-foot railroad boxcar without the use of stacking. Thus ~600MB was the capacity of a original single density data railroad car, though it was only only ~1mm in height.

While the floppy disc made data railroads possible, media stacking made them practical. A cylinder of bare floppy media ~10 feet high is roughly 3048 discs, so your standard railroad boxcar held ~1.8TB of floppy storage, in 1982! With an average rail speed of 18mph a single boxcar passes every ~1.5 seconds, which is ~1.2T terabytes or 9200 gigabits per second! By 1998 floppy media storage density had improved ~714-fold, yielding transfer rates of 6568800Gb/s or ~821 TB/s.

So why was floppy data railroad ultimately limited to this 'arbitrary' ~821 TB/s? Northern rail gauge of the US railway based on the English rail system which were based on tramways which used the same jigs used to build wagons whose wheel base was determined by ancient ruts that were left by Roman chariots which were sized to accommodate the width of two horses' asses. As not-quite debunked here.

So the short story is, any chain of decisions regarding technology leads back to some horse's ass.