Erasure Coding

Erasure coding is a data protection mechanism used in distributed storage systems to enhance fault tolerance and optimize storage efficiency. It provides redundancy by dividing data into multiple fragments and encoding it with additional parity fragments, enabling data recovery in the event of node failures.

Traditional data redundancy methods, such as replication, require multiple full copies of data, leading to significant storage overhead. Erasure coding improves upon this by using mathematical algorithms to generate parity fragments that allow data reconstruction with fewer overheads.

The core principle of erasure coding involves breaking data into k data fragments and computing m parity fragments. These k+m fragments are distributed across multiple storage nodes. The system can recover lost data using any k available fragments, even if up to m fragments are missing or corrupted.

Erasure coding has a number of key characteristics:

• High Fault Tolerance: Erasure coding can tolerate multiple node failures while still allowing full data recovery.
• Storage Efficiency: Compared to replication, erasure coding requires less additional storage to achieve similar levels of redundancy.
• Computational Overhead: Encoding and decoding operations involve computational complexity, which may impact performance in latency-sensitive applications.
• Flexibility: The parameters k and m can be adjusted to balance redundancy, performance, and storage overhead.