Erasure Coding

• Understanding Erasure Coding Offload

Erasure coding is a mathematical method to encode data in a way that it can be recovered in case of disk failures
Hardware Offload
Using Mellanox ConnectX-4 adapters, Erasure Coding calculations can be offloaded to the adapter's ASIC.
https://community.mellanox.com/docs/DOC-2414

• Erasure code introduction

Erasure Code is a theory started at 1960s. The most famous algorithm is the Reed-Solomon.
Erasure Codes usually defines the number of total disks (N) and the number of data disks (K), and it can tolerate N – K failures with overhead of N/K
E,g, a typical Reed Solomon scheme: (8, 5), where 8 is the total disks, 5 is the data disks.
RS (8, 5) can tolerate 3 arbitrary failures. If there’s some data chunks missing, then one could use the rest available data to restore the original content.
https://software.intel.com/en-us/blogs/2015/04/06/ceph-erasure-coding-introduction