Erasure Code with Shingled Local Parity Groups for Efficient Recovery from Multiple Disk Failures

The ever-growing importance and volume of digital content generated by ICT services has led to the demand for highly durable and space-efficient content storage technology. Erasure code can be an effective solution to such requirements, but the current research outcomes do not efficiently handle simultaneous multiple disk failures. We propose Shingled Erasure Code (SHEC), an erasure code with local parity groups shingled with each other, to provide efficient recovery for multiple disk failures while ensuring that the conflicting properties of space efficiency and durability are adjustable according to user requirements. We have confirmed that SHEC meets the design goals using the result of a numerical study on the relationships among the conflicting properties, and a performance evaluation of an actual SHEC implementation on Ceph, a type of open source scalable object storage software.