Dave Donatelli, a senior exec at EMC - the largest data storage vendor - predicted that high-end flash drives will replace high-end hard drives in 2 years. Is this the beginning of the end for disk drives?
What is a high-end hard drive?
Unlike the SATA or PATA drives in your desktop or notebook system, high-end disks share some important features:
- They're faster: 10k or 15k RPM and up to 3x the IOPS
- They're more reliable: 10x better read specs; 3-5x MTBF
- They use high-end interfaces like Fibre Channel (FC) or Serial Attached SCSI (SAS)
- They're much lower capacity: 74 GB and 146 GB capacities are most common; there are no 1 TB high-end disks.
- They're way more expensive: 10x per gigabyte
Vendors make huge volumes of SATA drives. But they make huge profits on their high-end drives. Most of them go into high-end arrays from EMC, IBM, Hitachi and HP whose prices start at $100,000 and soar into the millions.
The loss of this high-end, high-margin business has the drive vendor's attention. Seagate's suit against STEC, a maker of high-end flash drives, is part of an effort to claim this business for themselves.
EMC has measured STEC’s flash drives at 30x the IOPS of a high-end disk. And they give sub-millisecond access times. That alone would justify a premium over existing drives.
A 15k 74 GB Seagate SAS drive is about $175 or roughly $2/GB. A 2 GB Single Level Cell (SLC) flash chip is currently about $8/GB on the flash spot market. If flash keeps dropping at 50% a year they’ll be where the current disk price is in mid-2010.
High-end flash drives use a more costly and more reliable flash called Single Level Cell or SLC. These are spec'd at 1,000,000 read/write cycles. Write-leveling means that customers have no worries, even with database index files. Cheaper MLC flash, used in notebook drives, is now spec'd at 10k and will soon be even lower.
But that’s raw chip vs finished disk
The remaining question is how much does the chip controller and other infrastructure. STEC isn’t selling its 74 GB flash drives for $8/GB - $80/GB is closer to the mark. Volume will cover their engineering costs. PC boards are cheap. Then it's the cost of the flash chips.
Flash drives have other advantages: lower power; less cooling; higher MTBF and lighter weight. These are important when you have a couple of thousand drives in an array.
The Storage Bits take
Flash drives don’t need absolute price parity to win against high-end FC drives. Getting within 30% should do it for most people. Their performance advantages are worth at least that.
Of course the drive vendors aren’t going to sit still. Many have claimed disks are dead and they’re all gone. But this looks serious. It won't be easy to innovate against flash drives.
For us SATA drive users the death of the high-end disk, when it comes to pass, will mean that SATA drives will be more expensive as they shoulder the R&D costs that the high-end currently absorbs. Disk research will also be cut back when array vendors are no longer experiencing complex disk problems.
One thing it doesn't mean: flash notebook drives won't become any more attractive. Notebook disks are running about $0.40/GB and they'll be a quarter that by end of 2010. Not many people will pay 10x per GB for very little benefit.