Hybrid Hard Drives Just Need 8GB of NAND

judgecorp writes "Research from Seagate suggests that hybrid hard drives in general use are virtually as good as solid state drives if they have just 8GB of solid state memory. The research found that normal office computers, not running data-centric applications, access just 9.58GB of unique data per day. 8GB is enough to store most of that, and results in a drive which is far cheaper than an all-Flash device. Seagate is confident enough to ease off on efforts to get data off hard drives quickly, and rely on cacheing instead. It will cease production of 7200 RPM laptop drives at the end of 2013, and just make models running at 5400 RPM."

Comments

Of course! And you never need more than 640K RAM!

[Anonymous Coward]

No chance this is just the company saying this because they missed the boat on solid state drives?

Damn

[Nemyst]

This looks like Seagate desperately clinging to their old bastion. Even Western Digital bit the bullet and started working on pure SSDs. The problem with Seagate's calculations is that there'll come a time (not that far into the future) where NAND will be cheap enough to get a full SSD for only a moderate price hike over a HDD, all while getting all the benefits of a pure SSD drive. They risk getting left behind by clinging to the hybrid drive idea.

Re:Damn

[adisakp]

Hybrids aren't that bad an idea. You can get a 3TB drive for just over $100. HD Data is $0.03-$0.05 / GB. SSD's are still in the $0.80-$1.50 / GB range. That's a factor of 50X more expensive. You can't even buy a single 3TB consumer SSD and three 1TB SSD's will cost you around $2000 plus eat up half your SATA ports.

Although I do disagree on one point -- if a consumer uses ~10GB of data a day, I would overshoot and put in 16GB rather than 8GB in a Hybrid Drive -- it's better to slightly overprovision and almost never hit the platter part of the storage than to under provision and force yourself to the slower backstore. Plus the difference should only be less than $10 more for the drive.

One problem though with hybrid drives is they aren't necessarily faster than intelligent software caching to SSD's or of using a hardware controller (with possible software assist) that supports caching data from a HDD to a SSD (such as Intel Smart Response SSD Caching which has been on Motherboards since 2011).

Moving parts and fatigue

[barlevg]

Honest question: how do hybrid drives compare to traditional HDDs when it comes to wear? To they tend to fail more (less) often / die faster (live longer) than traditional drives? What about pure SSDs?

Re:Moving parts and fatigue

[Chas]

The lifespan issue with SSDs has three main factors.

1: Type of flash memory (SLC, MLC, TLC, in order of decreasing durability)
2: Size of the flash drive (larger drives have more room for wear leveling algorithms to work with, thus staving off flash cell burnouts due to exceeding maximum number of writes).
3: The amount of throughput on the flash drive. An expected heavy load is roughly 10GB/day. Doubling the load halves the lifetime of the drive. Quadrupling the load quarters it.

Granted, the cache on a Hybrid is being used a bit differently than how you would use a straight SSD. But, with such a small cache drive, you ARE going to wind up cooking it after a relatively brief period of time.

Re:Moving parts and fatigue

[tlhIngan]

The lifespan issue with SSDs has three main factors.

1: Type of flash memory (SLC, MLC, TLC, in order of decreasing durability)
2: Size of the flash drive (larger drives have more room for wear leveling algorithms to work with, thus staving off flash cell burnouts due to exceeding maximum number of writes).
3: The amount of throughput on the flash drive. An expected heavy load is roughly 10GB/day. Doubling the load halves the lifetime of the drive. Quadrupling the load quarters it.

Granted, the cache on a Hybrid is being used a bit differently than how you would use a straight SSD. But, with such a small cache drive, you ARE going to wind up cooking it after a relatively brief period of time.

Which for most users and usage scenarios, is basically forever. There's been a volunteer-run test of longevity which stresses an SSD until it fails by writing data to it continually. And the SMART data typically gives you plenty of advance warning - the Media Wear Indicator (MWI) tells you how many cycles are left in the array - once it hits zero, it means the number of write-erase cycles has hit the guaranteed limit and you're running in unknown territory (though there are usually still spare blocks and most will still have plenty of life). If you want guarantees, once the MWI hits zero, it's time to back up and get a new SSD. The tests run until the drive itself dies which tell you how long you have left. So you generally have a LONG indication of media wear out.

However, the biggest problem SSDs face is actually sudden loss and corruption of the FTL tables (the ones that map logical sectors to actual flash sectors). If you hear of SSDs dying prematurely, it's almost always because of table corruption. These tables contain things like sector translation, sector wear, dirty/clean bits, trim status, etc.

In the past, you could regenerate the tables from the spare area data (typically 16 bytes per 512 byte data area), but use of enhanced ECC algorithms consume that space up to accommodate better error handling. Plus it also meant way longer mount times as the controller had to scan the entire media for the information (many seconds long).

These days, controllers come with 512MB or more of RAM to hold the tables in memory for quick access. The problem is the tables are often written out lazily to storage, which means if you yank the power suddenly, the SSD might not be able to write the dirty data to stable media, or worse yet, it'll be in the middle of the write operation which leaves data in an unknown state.

Good SSDs often have piles of capacitors to serve as emergency power which can keep the array powered for a couple of seconds - more than enough time to flush the tables to storage and protect your data. Of course, this costs a lot more money and is usually present only in the top tier drives and enterprise class SSDs. If an SSD dies suddenly, it's usually because of this.

Hard drives use the back EMF produced by the spinning platters to perform emergency shutdown procedures, including retracting the heads.

Not in my experience

[swb]

I had a Seagate Momentus XT (750 GB hybrid) and I replaced it with a Samsung 750 GB SSD. The pure SSD solution is noticeably faster in all respects, especially in boot up, and this is with a machine now using Truecrypt whole disk encyption (wasn't using it on the Momentus).

The Momentus was a good upgrade until SSDs in the size I wanted were reasonably priced, but performance wise it isn't in the same league as a SSD.

The hybrid SSD solution really shows its weakness when you deviate from "normal" behavior, and this can be anything from an application upgrade, running Windows updates, or accessing stuff you don't use that much. Performance just seems back to dismal levels and I suspect that it takes a while for the cache to re-optimize if the deviating disk activity is at all intensive.

I think the hybrid concept is interesting, but I think you need more cache and a way to optimize the cache not just not most recently accessed blocks but for the operating system and applications in use, too.

Re:Hybrid drives on Linux?

[fnj]

SSHDs as implemented by Seagate do not require any support whatsoever in the host. Their caching algorithm does not care anything about the FS. It is block level. I have one working just fine in arch linux. Linux just sees it as any other HD, only it is much faster overall. Obviously you will never see any improvement at all in huge file copies.

WD has some lame Windows-only SSHD tech that does require special software on the host.

Re:What about games

[Anonymous Coward]

I truly doubt that anyone working at EA plays their games.

Re:Of course! And you never need more than 640K RA

[SJHillman]

I've used an SSD. Works great for my laptop and router, don't care for it for my desktop largely due to price. For $60, I can get an 80GB SSD or I can get a 2TB HDD. That 80GB SSD is going to require an additional HDD anyway for storage for many people.

Most consumers are still going to go with cheapest and, outside of the tech-oriented crowd, don't really care if they have to wait an extra few seconds. As far as I'm concerned, the SSD boat is still boarding passengers and is no where close to leaving just yet. Once SSD prices are more competitive with hard drives (which could be another decade or two at the least), then you can say that ship has sailed. Until then, cost will trump performance for the largest markets.

Re:Of course! And you never need more than 640K RA

[Traciatim]

If you don't have most of your stuff stored via a library or other link on an NSA or server . . .

Wait a sec . . . How do you access all of your data at the NSA? do they offer a subscription service or something?

Re:Of course! And you never need more than 640K RA

[fuzzyfuzzyfungus]

I have the suspicion that Seagate is planning quite specifically; but just don't care all that much.

The majority of orders will, presumably, be from OEMs looking to stuff HDD slots on the cheap, while still complying with the Win8 hardware certification requirements(most notably, resume in under 2 seconds) and possibly Intel's "ultrabook" requirements, which have their own I/O demands.

I suspect that Seagate's calculations of 'How cheaply can we build a drive that will satisfy the letter of the requirements that our customers need to meet?" were made with care, and aren't crap at all. They're just something of a lie if you expect that level of performance to be maintained under more stressful loads.

Re:Hybrid drives on Linux?

[FS]

I purchased one of those drives on the day it was available at Newegg for use in Linux, and then shortly after for a pair of them in RAID0 for a desktop (gaming) system where data integrity wasn't my main concern. In both systems I ran into firmware problems and could not natively flash them in the system that was running them. I pulled them into a bench PC I have and flashed them there and everything was fine. The issue had to do with power saving and would cause some pretty frequent hardware locking issues on both systems that was painful until I was able to resolve them. All 3 of the drives are benched now, but still work fine. I never lost any data due to the lockups - they would just hard lock the PC for a second or three and then continue working like nothing had happened.

In my experience this is typical early adopter fare.

Re:Of course! And you never need more than 640K RA

[cptnapalm]

So if I stick with 5400 RPM hard drives, I get doughnuts?

Re:Of course! And you never need more than 640K RA

[cptnapalm]

"Back in your day to load each webpage, did they deliver each bit by abacus via horseback?"

Isn't that how YouTube does it since Google bought them?

Re:Of course! And you never need more than 640K RA

[Hmmm2000]

Fumble fingers - meant to type NAS.

Sure you did.

Re:But their 5400RPM hybrid drives suck

[vux984]

I took into account cost, capacity and performance when choosing the drives.

But not battery life, apparently, which is the one area where 5400 rpm drives beat out 7200 rpm drives, and is possibly the reason they even exist. A 5400rpm hybrid would need to spin up even less and should do even better on the battery front. Not to mention that if you get a cache hit, it doesn't have to spin up at all, which is a big performance boost too.

So while "benchmark" performance might not be great, real world use might be substantial; as the hard drive could spin down more, and you could access the drive without spinning it up some of the time, possibly even most of the time.

There's definitely potential to be both markedly faster in real world laptop use scenarios and consume less battery with a hybrid. Whether that pans out in reality I don't know.

Re:Of course! And you never need more than 640K RA

[pushing-robot]

How do you access all of your data at the NSA? do they offer a subscription service or something?

Yes, they do!

Re:Of course! And you never need more than 640K RA

[ColdWetDog]

Man, Dropbox better watch out. Serious competition here.

But really, had the NSA pitched their product as a 'service', people would have fallen all over themselves to pay for it.

"Stores everything, everywhere! Never back up again!"

What's not to like?

Re:Of course! And you never need more than 640K RA

[ackthpt]

Fumble fingers - meant to type NAS.

Sure you did.

Absolutely! Would I lie to you, Mr. Joshua J. Fortenbras of 1104 W. Finster Ave, Quimby, NJ, who works at Asset Assure Investments (formerly Dewey, Cheatham & Howe). I trust you enjoyed your bacon and gerbil omlet, for breakfast this morning.