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SSD-HDD Price Gap Won't Go Away Anytime Soon
storagedude (1517243) writes "Flash storage costs have been dropping rapidly for years, but those gains are about to slow, and a number of issues will keep flash from closing the cost gap with HDDs for some time, writes Henry Newman at Enterprise Storage Forum. As SSD density increases, reliability and performance decrease, creating a dilemma for manufacturers who must balance density, cost, reliability and performance. '[F]lash technology and SSDs cannot yet replace HDDs as primary storage for enterprise and HPC applications due to continued high prices for capacity, bandwidth and power, as well as issues with reliability that can only be addressed by increasing overall costs. At least for the foreseeable future, the cost of flash compared to hard drive storage is not going to change.'"
Fairly sure that increases in capacity usually means increases in performance as well. I have not seen any ssd on the market today that illustrates otherwise. .50$ a gig on ssds. Prices have been plummeting. You can get a 256 gig drive for ~100$ . 1TB drives have been almost hitting the $400 mark.
We're down to less than
When 2TB ssd come on the market, you'll see the rest drop in price as well. I'm not quite sure where the author is getting their information. Check the price drops over the last two years and you can see they haven't hit bottom yet.
IIRC it would take 5+ high end HDDs to match the read/write speeds of a decent SSD. Add to it that a RAID 0 has no safety so if 1 drive faults, the whole thing is done. A single SSD (like my Corsair Force GT) will r/w at ±500MBs. You just can't beat that right now.
For most applications, the performance bottleneck with a hard disk is seek latency, not raw streaming bandwidth. There is basically no way for a mechanical hard disk to match the seek performance of a SSD.
Doesn't creating a striped RAID make up most of the performance issues from using a HDD over a SSD? At that point, it's more the bus or CPU that's a limiting factor?
No RAID does not allow HDD to perform as SSDs. RAID increases throughput but it does not decrease access time, which in many cases is fare more important than throughput.
Having a seek time of 8ms when you are working with many small files is a huge hit on performance. The seek time of SSDs is well under a millisecond. RAID does not help this no matter how many disks you stripe.
640K ought to be enough for anybody.
No, it's not asinine, but a nod to the intellect of the reader. It demonstrates that the writer has confidence that the reader understands what they're saying. It demonstrates humour and it ...
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Say what?!?
Crucial M500 480GB = $240 or $.50/GB
WD BLACK SERIES WD4003FZEX 4TB = $260 or $.065/GB
Seagate NAS HDD ST3000VN000 3TB = $139 or $.046/GB
prices are current at newegg
The HDD's are around 10x as cheap per GB.
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So the backup disk is online in the same system? Sounds dangerous.
Well, 256GB SSD ought to be enough for anybody, and is relatively affordable.
enough is never enough.
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I think one of the big bonuses of the SSDs hitting the mainstream is people (and manufacturers) are re-examining how much capacity people actually need. For a while there was a trend of just throwing the biggest drives possible at every machine made since a bigger number looks better then a smaller number on marketing material, but it meant a lot of people bought computers with drives that far exceeded their actual use cases.
For most people 256GB is more then enough, depending on how they are using it. Though it is no where near enough for other uses.
Personally for my use case, I have both. a 128GB drive for OS and applications, and 1TB HDD for data. If I kept my data on the SSD it would fill up rapidly, so it is not enough for this 'anybody' at least, and I know people who burn through space a lot faster then I do.
We need reliable hybrid drives with 120-160+ GBs of flash memory, instead of the ridiculously worthless 4-8 GB ones we have now.
A hybrid with a 1:30 or 1:20 ratio of flash to platter (200 GB for 4 TB for instance) would pretty much be perfect for anyone, even enterprise applications if RAID controllers cooperated with the hybrid caching properly.
We do not need 100% flash, just give us a practical median.
In fact, I guarantee if someone made a hard drive with a controller with an mSATA slot for adding a SSD and offered the controller to be setup as pass-through (act as two drives) or caching (SSD keeps a cache of platter), it would sell like crazy.
An mSATA would fit easily beneath a standard 3.5 inch platter hard drive.
http://www.notebookreview.com/...
Even if this were true, you're creating an artificial advantage. How will a RAID array of HDDs compare to a RAID array of SSDs?
PCIe SSDs are even faster. The one in the Mac Pro can hit 1gig read/write, for example.
You'd need a lot of disks to come even close to that. :)
Non impediti ratione cogitationus.
Seek time is the time for r/w head movement (closer or farther from the disk center) PLUS the wait time until the wanted data is rotated under the read/write head. So, unless you go with r/w heads for each sector on the hard drive, you can't reduce part of the seek time. And you could rotate the disks faster (like in SCSI 15k rpm disks), but there's a limit there too.
Will HDDs ever be performance-competitive at the same cost to SSDs? At the current technology level, no. Will SSDs ever be price-competitive at the same capacity? Hardly, considering adding another platter and r/w head to a hard drive is a quite inexpensive way to increase capacity, while adding another set of flash memory chips is an expensive way to increase capacity.
(oh, and a read/write head for each data strip was used in the 50s and 60s - see magnetic drum memory).
Absolutely not. Even 100 RAIDed HDDs (in any RAID type) will struggle to match the IOPS achieved with a single SSD.
Typical IOPS for a 7200 RPM HDD: 80
Typical IOPS for a modern consumer level SSD: 20,000-100,000
http://en.wikipedia.org/wiki/IOPS
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10 times ago I heard about IBM and others working on new technologies to replace memory. Holographic cubes, MRAM, ... Are they still 10 years away?
No RAID does not allow HDD to perform as SSDs. RAID increases throughput but it does not decrease access time, which in many cases is fare more important than throughput.
Having a seek time of 8ms when you are working with many small files is a huge hit on performance. The seek time of SSDs is well under a millisecond. RAID does not help this no matter how many disks you stripe.
RAID does not always mean stripe. Mirroring does improve seek performance. It increases the chance that a drive has a head closer to the data you want already (if the implementation is smart enough to be aware of this), and it also allows seeks to occur in parallel (which isn't exactly the same as latency reduction, but is fairly equivalent in practice since drives are almost always busy).
Doesn't creating a striped RAID make up most of the performance issues from using a HDD over a SSD? At that point, it's more the bus or CPU that's a limiting factor?
No. My raid0 and Raid5 setups don't even come CLOSE to comparing to my SSDs. I've been running 2 SSD Raid0 and OMG the speed diff is absolutly crazy. Yes when one does all data is toast and they DO die. I was dumb and bought 3 OCZ drives and all 3 have died at least once in the last 1.5 years but the replacements have held up pretty well. I totally expect to lose one at any time so I have really good backups of my C: Drive :) everything else goes on my spinny platters.
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I was shocked when we got one of the MacPro6 units in, and I ran a disk benchmark on it. It was sustaining 950MB/sec, which is good enough to write 10-bit YUV 4:2:2 2k video at 117fps.
That is a realm you could only really get to with fiber channel previously, or a ridiculously expensive PCI-E card with SLC flash.
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PCI-E SSDs were available on PCs long before debuting on macs. They often run much faster as well, as they can use RAID0 striping. I've seen drives that use a quad RAID0 pushing utterly insane numbers for long term storage at the cost of not letting TRIM commands through.
RAID 10 and RAID 0+1 shouldn't be used interchangeably. RAID 10 is striped mirrors, and 0+1 is mirrored stripes. Both fail if all copies of mirrored data are lost, but with RAID 10 that's only 1 disk to worry about after the first failure while with RAID 0+1 it could be any of the disks in the remaining stripe set, which is at least 2.
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No we don't. Hybrid drives are stupid. The added software complexity alone makes them a non-starter for anyone who wants reliability. The disparate failure modes make it a non-starter. The SSD portion of the hybrid drive is way, WAY too small to be useful.
If you care enough to want the performance benefit you either go with a pure SSD (which is what most people do these days), or you have a separate discrete SSD for booting, performace-oriented data, your swap store, and your HDD caching software.
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Hilariously, that is the first actually valid reason to switch from 7 that I've ever heard.