Fast Product-Matrix Regenerating Codes
  Distributed storage systems support failures of individual devices by the use of replication or erasure correcting codes. While erasure correcting codes offer a better storage efficiency than replication for similar fault tolerance, they incur higher CPU consumption, higher network consumption and higher disk I/Os. To address these issues, codes specific to storage systems have been designed. Their main feature is the ability to repair a single lost disk efficiently. In this paper, we focus on one such class of codes that minimize network consumption during repair, namely regenerating codes. We implement the original Product-Matrix Regenerating codes as well as a new optimization we propose and show that the resulting optimized codes allow achieving 790 MB/s for encoding in typical settings. Reported speeds are significantly higher than previous studies, highlighting that regenerating codes can be used with little CPU penalty. 
Nicolas Le Scouarnec
cs.DC cs.IT cs.PF math.IT