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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."
Also, I thought the world was going SSD anyway, which is thinner, not thicker?
Multi-platter was always a good idea, I assume it stopped in a desperate attempt to cut costs.
8" hard drives often had 4 or even 8 double sided platters - and SCSI interfaces! Early 5.25" drives often had two, double sided platters. They desperately needed to access more data with less head movement because they had quite low areal bit density and used floppy-derived stepper motors for head positioning!
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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 on each side of the platter might be a better solution, one for the inner part and one for the outer.
There are other form factors other than the typical low profile 3.5".
In particular there is the "half-size" thickness, witch is the thickness of 5.25" bays. It was a rather common form factor for 3.5" SCSI drives.
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.
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.
Taller, more heads, smaller platter, less seek distance -- the logical end point is the drum! I'm sure we can do better than the FH-1782 today.
Everything old is new again...
+1 for repeating yourself almost exactly. +5 For not being correct. There is more involved in managing data center performance than simple access times or temps. Even with multi-ton cooling, a data center is *still* looking at a lower operating cost to spin hot drives than to use super $$$ high-capacity SSDs. SSDs do not solve any problems for data centers, because individual drive access time is not interesting to a data center. Rather, the performance in $ per KIOPS for the entire array is the real measure of performance.
the cost of manufacturing an SSD is about 25% that of manufacturing a platter HDD
Really? I think if that were anywhere near true it would be reflected in the cost of SSDs. Do tell, where can I buy a 4TB SSD for $30!
The disk drive market is pretty competitive. I tend to think if SSDs cost 25% of an HDD to make, they'd be selling for a lot less than they are. And with Google's buying power probably even less for them.
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.
<blink>down the rabbit hole</blink>
The research paper is not available. Any pointers ?
Multi r/w heads aren't a new concept. Some of the really old drives had them, and in fact the very original magnetic recording "disks" had a r/w head per track. I think in the trade off of more heads versus faster spinning, faster spinning won out.
I seems that there should be a market for more platters, in a slightly different form factor.
Someone needs to invent a RW 'bar' that is long enough to go from the spindle to the outmost track. Any point on the bar would be capable of reading or writing. Instead of moving a narrow head on an actuator arm, you just 'activate' (electronically) the part of the bar that is currently over the track you want to access. If cheap enough, you could install a dozen of these bars all around the disk so that you would never need to rotate more than 30 degrees of a circle before a sector you want is under one of the bars. Rotational latency would be very low even on a 2000 rpm drive. Even better would be the ability to activate multiple points on the bar simultaneously so that you could read or write multiple tracks at the same time.