For more than 50 years, the disk drive has been at the center of computing architectures and the Internet, but there's mounting evidence that this is going to change powerfully over the next decade.
This past week I attended Storage Networking World, one of the storage industry's more popular meet-ups, and the most discussed topic was flash-based disk storage. Apple Inc. (Nasdaq: AAPL) first introduced NAND (flash) storage on its iPod Shuffle in early 2005, and while some dismissed the announcement as a niche for toys, others began to look at pricing forecasts and realized that, for certain applications, flash-based storage would begin to replace spinning disks in the early part of the next decade.
In fact, selectively, it's already happening today. Virtually every major system and storage supplier has announced support for NAND flash drives in storage arrays. NAND drives have much better response times and faster access times than spinning media. The disadvantages are cost and reliability -- i.e., the number of writes to each memory cell is limited and has to be managed with additional layers (and more cost).
But for Internet applications, where much of the activity is simple reading of the disk, this is potentially good news. Specifically, flash prices are dropping faster than those of spinning media and will begin to replace spinning disks in certain applications. New architectures are possible where the highest-performance Internet data (e.g., indexes, search metadata, certain database activities, etc.) can be serviced from flash-based storage, while less performance-intensive data will be placed on the very highest-capacity, lowest-cost spinning devices, and, in an effort to save energy, spun down when not in use.
It is important to distinguish between high-performance drives and high-capacity drives. The Achilles heel of disk drives is access time limited by rotational delay. Expensive controllers with RAM caches have been designed to mitigate this problem. With the high performance and low access times of NAND storage, the major type of drive that is likely to be initially replaced by NAND devices are high-performance Fibre Channel (FC) drives. Although high-capacity disk drives (SAS or SATA) may eventually be replaced by NAND drives, that is well beyond any near-term planning horizon for users and vendors.
So one key planning question is whether NAND storage will obviate the need for high-performance FC disk drives. And if so, when?
The chart above shows three price curves for flash at varying rates of decline (50 percent, 60 percent, and 70 percent annually). Current trends since last summer show that the actual reduction of NAND prices is about 60 percent per year. At this rate of comparative reduction, FC drives will be obsolete in less than three years time (2011-2012).
While much of the Internet's data will reside on spinning disk for quite some time, it's inevitable that flash technologies will begin to permeate computing architectures and alleviate an age-old problem that mechanical disks were never truly well suited for computer applications.
— David Vellante spent 15 years at IDC and is a founder of The Wikibon Project. He can be reached on Twitter at @dvellante.