Erasure coding definition
Erasure coding is a data protection technique used in computer systems and storage to ensure data integrity and resilience. It involves breaking data into smaller pieces, generating additional pieces called ”parity”, and distributing them across multiple storage devices or servers (known as data redundancy). Doing so means that if any of the devices storing the data fail, or data chunks are lost, the original data can be reconstructed.
How erasure coding works
- The original data is divided into smaller chunks or fragments (called “parity”).
- Additional parity chunks are generated by performing mathematical operations on the data chunks. Parity chunks contain redundant information that can be used to reconstruct lost or damaged data.
- The data chunks and parity chunks are distributed across different storage devices or servers in a way that ensures redundancy and fault tolerance. This distribution can be done using various schemes, such as Reed-Solomon or XOR-based algorithms.
- If data is lost or a device fails, mathematical calculations are applied to reconstruct the missing or damaged data using the available data and parity chunks.
Benefits of erasure coding
- Fault tolerance. Erasure coding helps ensure that even if one or more devices fail or data chunks are lost, the original data can be reconstructed using the remaining data and parity chunks.
- Error detection. Erasure coding includes mechanisms to detect and correct errors in the stored data.
- Storage efficiency. Erasure coding requires less storage capacity to achieve the same level of data redundancy.