Is the Time Finally Right For Hybrid Hard Drives? 311
a_hanso writes "Hard drives that combine a traditional spinning platter for mass storage and solid state flash memory for frequently accessed data have always been an interesting concept. They may be slower than SSDs, but not by much, and they are a lot cheaper gigabyte-for-gigabyte. CNET's Harry McCracken speculates on how soon such drives may become mainstream: 'So why would the new Momentus be more of a mainstream hit than its predecessor? Seagate says that it's 70 percent faster than its earlier hybrid drive and three times quicker than a garden-variety, non-hybrid disk. Its benchmarks for cold boots and application launches show the new drive to be just a few seconds slower than a SSD. Or, in some cases, a few seconds faster. In the end, hybrid drives are compromises, neither as cheap as ordinary drives — you can get a conventional 750GB Momentus for about $150 — nor as fast and energy-efficient as SSDs.'"
It'd better happen quick then (Score:5, Insightful)
If there is to be a time for hybrid drives, the window on it is fast closing. As SSDs get cheaper and cheaper more and more people will opt to just go that route. Most people don't really need massive HDDs and so if smaller SSDs get cheap enough that'll be the way they'll go. They don't have to be as cheap as HDDs, just cheap enough that for the size people need (probably 200-300GB for more people) they are affordable enough.
For me personally, the time already came and went. I was very enthusiastic about the concept of hybrid drives, particularly since I have vast storage needs (I do audio production). However no hybrid drive for desktops was forthcoming. Then there was a sale on SSDs, 256GB drives for $200. I picked up two of them. $1/GB was my magic price when I'd be willing to get them. Now I have 512GB of SSD storage for OS, apps, and primary data. That is then backed by 3TB of HDD storage for media, samples, and so on.
A hybrid drive has no place. I'd certainly not replace my SSDs, they are far faster than any hybrid drive (even being fairly slow on the SSD scale). Likewise I have no real reason to upgrade my HDDs, they serve the non-speed intensive stuff.
While I'm willing to spend more than most, it is still a sign of things to come. As those prices drop more and more people will say "screw it" and go all SSD.
Re:It'd better happen quick then (Score:5, Insightful)
Right, but it didn't happen quickly. These is only one model of a hybrid hard disk available, which makes it unsuitable for any serious use in mass production. Also Seagate now tell us that their previous version was actually crap, and the new one is much much better. The price is lower but still high - about 100 dollars for 8 GB of flash. For that money you could get an SSD with 48 GB - and put all your system data on it.
This is a niche product, designed for laptops with only one disk slot that require both fast access and high storage. It is heavily compromised in both aspects, and the price is outrageous.
Re:It'd better happen quick then (Score:0, Insightful)
But a disadvantage of SSD's is that you can only write to them so many times. They corrupt more easily than regular hard drives and people, with their operating systems, are constantly writing to drives and moving things around.
One thing that I wonder though is why don't hard drives contain more cache memory? 32MB of cache memory is very little, adding substantially more cache memory could easily increase speed without increasing cost very much while reducing ware and tare on a drive, especially on an SSD drive.
Re:It'd better happen quick then (Score:5, Insightful)
> Most people don't really need massive HDDs
Are you kidding me.
Record FRAPS of your gaming sessions, photography (or RAW), record and edit anything with any modicum of quality? Save said media and final encodings?
Age of conan, 33 GB. LA Noire13 GB. Mortal Online, 30 GB.
That is stuff ordinary people do, not audio producers.
Re:It'd better happen quick then (Score:3, Insightful)
Frankly I'm not sure the write thing's as much of an issue as people make out.
MTBF for HDD and SSD are both ludicrously high these days. I'd be more worried about the mechanical failure of an HDD than reaching the write limit on an SSD.
Re:It'd better happen quick then (Score:5, Insightful)
The rewrite figures are going to shit as they move to smaller processing tech, 25nm eMLC is already down to 3000 writes/cell, they say you won't get $1/GB at normal prices until we get 19nm which at least some say will be down to 1000 writes. That you're getting 500MB/s write speed is nice, but if you actually start using that regularly you'll burn through the disk in a matter of months. My first SSD - which I admit I abused thoroughly - died after 8-9000 writes average (was rated for 10k) after 1.5 years. My current setup is trying to minimize writes to C:, but I still don't expect it to last nearly as long as a HDD. Using it as a read-heavy cache of static files may be a better way to boost it for those that haven't got hundreds of dollars to spend every time it wears out.
I think there's a place for these. (Score:3, Insightful)
A hybrid drive would be great in my laptop. It doesn't have room for "storage" drives and a 600GB SSD would be heinously expensive. You could also put one in a USB 3.0 external enclosure (I assume they can work like that.) That would give you a nice trade off between speed, capacity and, most importantly, portability.
That seems to be what Seagate is thinking too. Since the drive is in the 2.5" form factor.
Re:It'd better happen quick then (Score:4, Insightful)
I'll lecture you about my practical usage versus your theoretical bullshit.
I used a SSD for 3 years now and I have zero problems. It was cheap and it has literally transformed the way I use my computer. Its so fast I'd never go back to mechanicals.
On the other hand, I had 3 mechanical drives failing on me, after an average use of 2-3 years.
Until you actually try SSDs, don't lecture other people about them because you don't know what you're talking about.
Realize the limitations... (Score:5, Insightful)
Hybrid drives, and even all of the hybrid RAID controllers I've looked at, only use the SSD for read acceleration. They aren't used for writes, from what I could tell from their specs. So you're almost certainly better off upgrading your system to the next larger amount of RAM rather than getting a hybrid drive.
Personally, I looked at my storage usage and realized that if I didn't keep *EVERYTHING* on my laptop (every photo I'd taken for 10+ years, 4 or 5 Linux ISOs, etc) and instead put those on a server at home, I could go from a 500GB spinning disc to an 80GB SSD. So I did and there's been no looking back. The first gen Intel X-25M drives had some performance issues, but since then I've been happy with the performance of them.
Re:"No" (Score:3, Insightful)
That's precisely what a hybrid HDD does, except it takes the decision regarding what will benefit most from going in the SSD out of your hands.
Re:It'd better happen quick then (Score:3, Insightful)
"They will age in a more linear fashion. A 50 year MTBF of an SSD drive is actually a plausibly useful data point, whereas a 200 year MTBF of a hard disk is a BPOS."
Theoretically that may be true, but SSDs are still young enough that I give a lot of weight to "anectodal evidence", and the majority -- in fact almost all -- of what I have heard is that they actually tend to fail catastrophically.
As far as I am concerned, a "wait and see" approach is still feasible before I spend a bunch of money.
Re:It'd better happen quick then (Score:5, Insightful)
The rewrite figures are going to shit as they move to smaller processing tech, 25nm eMLC is already down to 3000 writes/cell, they say you won't get $1/GB at normal prices until we get 19nm which at least some say will be down to 1000 writes.
Based on 3000/25nm tech, the new erase cycle limits will be ~58% (1700/19nm) but the storage capacity per area will increase by ~70%.
That you're getting 500MB/s write speed is nice, but if you actually start using that regularly you'll burn through the disk in a matter of months.
The smaller tech has just as much "heavy use" as the larger tech when equal amounts of board area are dedicated to flash chips. A board with 1 TB of 1700-cycle flash can take a serious write pounding even with considerable write amplification. The same board on the 25nm tech would only have 588 GB of 3000-cycle flash/
"Heavy use" doesnt mean "fastest possible erases." I don't know what you think heavy use means, but even extreme pounding scenarios (such as cycling the entire 1 TB once per day, something you might see in a non-incremental backup server) still gives these drives years of cycles to "blow" through. You could technically kill this theoretical drive in a little over a month but that says nothing about what a "heavy user" will actually witness.
The people solving write needs extreme enough that they would burn through the cycles of this theoretical 1 TB drive in less than a year are dedicating a lot more than a single 1 TB drive to their data volume problem
Re:It'd better happen quick then (Score:2, Insightful)
If you value your data that much (and I understand if you do, because I value mine as well), you shouldn't be trusting either the SSD or the conventional HD. You should be backing up that data to a second device either way, at which point whether or not it is SSD or HD is irrelevant.
My machine is all SSDs for what its worth. Data files and system files are all on SSD. Of course the personal data files are all backed up to a server built of conventional HDs that sits in my wiring closet. Not because I think the conventional HDs last longer, but because their cheaper. The important thing is that the data is in two places at the same time, and that there is time to do a replacement if one of them fails before the second copy also fails. Whether they are SSDs or HDs is entirely a question of performance vs. cost for me. On the actual desktop, I value performance and am willing to pay the extra cost, so I have SSDs. On the backup device, performance is irrelevant and cost is what I care about so I have HDs.
Now if you are afraid it may be a waste of money because you think it will fail too soon to be worth the cost, that's a fine argument. Though I wouldn't agree with you.
But if you say you are not using SSDs on your desktop or laptop because you don't want to risk losing your data, all that means is you don't value your data enough to back it up, because if you were backing it up, that wouldn't be a concern. :p
Re:It'd better happen quick then (Score:5, Insightful)
MTBF is not the failure rate of a single disk, it's the average failure rate of disks used in an array. If you have a type of disk with a 100,000 hour MTBF, and use 100 of them (whether in a raid array, a cluster, or 100 individual desktops in a company). Then you will (roughly) replace one disk due to failure for every 1000 hours (100,000 MTBF / 100 disks), or 40 days.
It doesn't try to pretend that a single disk lasts 100,000 hours. That's stupid.
Re:It'd better happen quick then (Score:4, Insightful)
If you would care to read up what MTBF actually means and how it is used you would not say it is BS.
If you have a drive with MTBF of 171years, how likely is it will fail during its expected usage period of 5 years? It is 2.88%
What is the likelihood a drive with 230 years MTBF will fail during the next 2 years? It is 0.86%
The formular is p(a) = 1-e ^ (- a/mtbf)
If you can not work with that, don't balme the engineers that can.