AND DAN

Both physical disk failure and logical errors may cause data loss for enterprise ap-plications. It is imperative to adequately detect anomalous events and identify malicious activity that would affect Cloud users ' data assets. It is therefore becoming increasingly important for RAID-based storage systems to be able to track data changing of any point-in-time and to provide Continuous Data Protection (CDP). We propose a novel hy-brid RAID6 architecture, referred to as, HR6TAP, which is able to provide block level data changing information for detection and subsequent analysis of incidents and to re-cover data from both arbitrary two concurrent disk failures and logical errors. We devel-oped three flavors of HR6TAP, that is, HR6TAP-RL/SL/ML, which have their own characteristics. Extensive trace-driven evaluations by using DBT-2 and file system benchmarks demonstrate that the proposed HR6TAP scheme outperforms existing HDD-based or SSD-based RAID6 in terms of performance, energy efficiency, failure recovery ability and reliability