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.'"

Re:RAID?

[Anonymous Coward]

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.

Re:RAID?

[Anonymous Coward]

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.

Re:oh how wrong this is

[afidel]

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.

Re:We live like kings and queens already

[jythie]

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.

Re:RAID?

[RyuuzakiTetsuya]

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. :)

Re:RAID?

[Mad Merlin]

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 [wikipedia.org]

Re:RAID?

[TheRealQuestor]

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.

Re:RAID?

[MachineShedFred]

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.

Re:RAID?

[Luckyo]

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.

Re:RAID?

[operagost]

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.