This isn't a turn key utility, but it's relatively easy to call from Go. It allows you to set the number of data shards and parity shards, it's pretty fast. I

This isn't a turn key utility, but it's relatively easy to call from Go. It allows you to set the number of data shards and parity shards, it's pretty fast. It's at https://github.com/klauspost/reedsolomon Seems like a pretty common solution, I suspect there's other libraries for popular language/platforms.