Solid-State Disk Technology Provides Fast Access to Apps, At a High Cost


When K-mart launched its e-commerce site, called, a few months ago, this nationwide retailer turned to solid-state disk technology, not mechanical disk drives, to provide lightening fast delivery of e-mail message to customers. In fact, David Hill, the Aberdeen Group's research director for storage, says that solid-state disk technology has become useful for Web-based applications where mechanical disks can't read and write fast enough to keep up with the fast processors and database systems. For example, both Yahoo and EBay use solid-state disks to store frequently used files, such as database logs of transactions, which are too large and too slow for mechanical disks to handle.

At K-mart's, solid-state disks help to accelerate the SendMail application by blasting out 250,000 mail messages an hours. This speed is about 100 times faster than what the company could get from server hard disks, according to a source at Imperial Technology, the provider of K-mart's solid-state disks.

Solid-solid disks, which have their roots in the mainframe-era, earn their keep by storing the handful of frequently used files that ate at the largest causes on input/output, or I/O bottlenecks. These common traffic jams occur when a server's central processor has to wait for disks to complete a read or write before it can move to the next transaction.

By relocating these few key files from mechanical disk drives to a speed demon of a solid-state disk drive, you can increase an application's performance by up to 50 percent. This increase in speed enables you to put off purchasing an expensive, new high-performance server, as well not having to deal with the cost of managing this server.

Ironically, solid-state disks aren't disks at all. They consist banks of dynamic RAM chips packed into a cabinet and configured to appear to a server as just another storage device containing disk drives. Solid-state disks usually contain one mechanical disk drive. It acts as a battery-powered safety net where data can be stored temporarily in case an electrical failure shuts down the memory chips.

Undoubtedly, solid-state disks can make life happier for database administrators and systems administrators. But there's a catch - the price. Storing data on a solid-state disk can range from $10 per megabyte to $15 per megabyte as opposed to 5 cents per megabyte with a mechanical disk drive. To this end, organizations, such as Kmart, Ebay, and Yahoo, can easily cost justify putting their most used files on solid-state disks.

Server consolidation may be another area where you can perhaps cost justify using solid-state disks and eliminating I/O bottlenecks. Centralizing IT operations can mean fewer, more manageable servers. But server consolidation often results in concentrating data traffic. The government has stepped up its efforts to use solid-state disks to support server consolidation.

Rather than use solid-state disks to eliminate I/O bottleneck, you can try to boost server performance by increasing the amount of server's internal main memory. The drawback here is that if the server crashes of locks up, the data in memory gets lost. On the other hand, solid-state disks don't have this problem. As standalone devices, solid-state disks come with their own backup capabilities.

Today solid-state disks appear a bargain compared to their $10,000 per megabyte price tag in the mid 1980s. They also have shrunk from the size of a refrigerator to a rackmounted pizza box.

Elizabeth M. Ferrarini is a free-lance writer from Boston, Massachusetts


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