[jumpmanjr]

I applied Bendord’s law against hard drive bad block addresses across 20,000 enterprise storage arrays that called home. In theory, drive bad block LBAs should map perfectly to Benford’s distribution. In our system, there were a number of anomalies. Digging in further, I discovered that the engineeers periodically had the drives seek to a certain location, and write a status block. This happened frequently enough that it interrupted the drives internal “swirl” algorithm that was developed to keep the head from carving a “canyon” into the medium. At a microscopic level, our drives looked like the Grand Canyon.

[romwell]

This is fascinating!

The only time I've heard people talking about using Benford's law to detect anomalies was in the context of election fraud. This is much more exciting and practical.

[jumpmanjr]

Thanks! Unfortunately the raid controller needed those blocks during boot time, or it couldn’t recover properly. I may have convinced the engineers to turn on “read after write” for those blocks.

After explaining this discovery to my manager, I also explained how Benford’s law could be used to detect fraud in his corporate travel expenses. He seemed more interested in that application.....