Optimizing Systems to Use Flash Memory as a Hard Drive Replacement

Optimizing Systems to Use Flash Memory as a Hard Drive Replacement

By Om Narasimhan
April, 2008

Flash devices offer a possible alternative to traditional hard drives. Based on solid state, nonvolatile memory, flash devices can be more robust and less expensive than disk drives. When implemented properly, flash devices can boot systems faster and provide higher performance. Flash devices also naturally stay cooler than hard drives and can operate across a wider range of thermal conditions. However, installing an operating system in the default manner on a flash drive may not result in the best device performance or longevity. By following the guidelines in this Sun BluePrints article, a system equipped with flash technology can actually exceed the performance of a server with a hard drive and operate over a similar lifespan.

This article explains how customizing a Linux operating system configuration can help enable effective use of flash memory as a hard drive replacement. The article addresses the following topics:

• "Flash Overview", discusses the basic principals of flash technology and the potential for capacity degradation of this storage medium.
• "Prolonging Flash Life by Reducing Writes", provides a detailed review of methods to make flash last longer under the Linux operating system. Tactics include redirecting log output, moving temporary space, managing swap space effectively, moving frequently used files off of flash storage, and tuning the file system to minimize the number of writes needed for maintenance activities.
• "Putting it all Together", summarizes the main points presented in this paper.

About the Author

Om Narasimhan is a software engineer in the Systems Group at Sun Microsystems. Before joining Sun two years ago, he worked with several startup companies in Silicon Valley and Bangalore, India. He has been working with the Linux kernel, device drivers, board support packages (BSPs), and other related technologies for more than seven years. Om has authored a number of articles and HowTos in different print media and web sites including kernelnewbies.org.

Acknowlegements

The author would like to recognize Phillip Martin, who created a first draft of this paper while a software engineer in the Systems Group at Sun Microsystems.

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