Hi Brian, thanks for open-sourcing Backblaze's JavaReedSolomon, which is really well-written. A few months ago I ran into an issue with Reed Solomon coding throughput not saturating the write throughput of 16 drives, and wrote a new Reed Solomon module based on Cauchy matrices: https://github.com/ronomon/reed-solomon

The Cauchy matrices remove the need for a table lookup to do the Galois multiply, replacing it with pure XOR. Together with other optimizations, this gives nearly 3x-5x more coding throughput for the same (17,3) parameters, assuming you're still using your open-sourced JavaReedSolomon in production. I don't know if Reed Solomon coding throughput is a factor in your rebuild times?