Durability Evaluation of Erasure Coding Applying Risk-aware Data Protection in Large-scale Disasters

When a site is damaged by a major disaster, there is a risk of large-scale data loss within the premises or isolation from the Internet due to network disruption. To achieve both data durability and availability from the disaster area, Risk-aware Data Protection (RDP) has been proposed to distribute redundant data to neighboring sites based on the disaster risk. However, RDP has only been studied using a method called replication, while Erasure Coding (EC) applied to RDP is still unexplored. Therefore, the challenge of this study is to quantitatively compare the effectiveness of these methods in RDP. For this purpose, we formulate evaluation indicators to measure the remaining data ratio after a disaster; and then propose how to apply several existing combinatorial optimization algorithms to RDP. Based on the results of experiments, we determined that EC performs better than replication if the probability of site damage is small.