Practical Scrubbing: Getting to the Bad Sector at the Right Time
Latent Sector Errors (LSEs) are a common hard disk failure mode, where disk sectors become inaccessible while the rest of the disk remains unaffected. To protect against LSEs, commercial storage systems use scrubbers: background processes verifying disk data. The efficiency of different scrubbing algorithms in detecting LSEs has been studied in depth; however, no attempts have been made to evaluate or mitigate the impact of scrubbing on application performance. The authors provide the first known evaluation of the performance impact of different scrubbing policies in implementation, including guidelines on implementing a scrubber.