ERP: An Efficient Rewrite Scheme to Improve the Inline Deduplication Restore Performance in Backup Systems

Data deduplication is an effective technique to reduce the amount of redundant data, which is widely used in backup systems. To reconstruct the original backup data, restore is a typical procedure in inline deduplication, which brings read amplification when duplicate chunks are shared among various data streams. Rewrite is a cost-efficient method to improve the inline deduplication restore performance by writing the fragmented duplicate chunks repeatedly. Although several rewrite schemes are proposed to improve the restore performance, they either decrease the deduplication ratio or increase the temporal overhead of the rewrite procedure. This is because existing rewrite methods select inappropriate number of containers, or ignore the inter-container redundancy information. To address the above problems, we propose an E ffective –Region -Partitioning based rewrite scheme (ERP), which improves the restore performance in backup systems and ensures a high deduplication ratio. The key idea of ERP is to effectively narrow the selection range and choose a flexible number of containers by investigating the inter-container redundancy information. To demonstrate the effectiveness of ERP, we conduct several experiments in a deduplication backup system. Compared to the state-of-the-art rewrite schemes, the results show that ERP reduces the rewrite cost by up to 97.71%.