Study On Data Migration Technology In HSM

With the continuous development of informatization and digitization,the rate of data has grown exponentially. Large amounts of data need to store and acess, which has brought a great burden to the storage system. In order to store the rapidly growing data, storage technology in recent years has been rapid development and the performance of storage devices has also been improved, a number of new storage structures and technical emerged in this time. These technologies alleviate the pressure of the storage to some extent, at the same time it also brings a substantial increase in storage costs and makes storage management more complex. In this case, hierarchical storage as an important role in storage area has been more and more concerned. Hierarchical storage ideas as an concept of playing storage device performance effectively, improving data access rates and reducing storage costs has a very broad application prospects and becomes a research focus. The core of hierarchical is storage data migration technology, the technology migrates data between different memory hierarchy, meanwhile ensuring consistency of data access during the migration process.The paper studies data migration technology in hierarchical storage system architecture. The specific contents are as follows:Firstly, the paper studies the current mainstream network storage technology; Then we compare and analysis the performance of RAID, SSD,VTL,CD-ROM and other present storage devices, to make a bedding for construction of hierarchical storage platform.Secondly, the paper studies the current data migration strategy, the method of High-Low Level based on storage space and the method of Cache replacement migration algorithm based on data access rate. Based on the idea of information lifecycle management, we propose a data valuation model(MSDV).The model combining with the data migration process control strategy try to reduce the effect on the system and further improve the hit rate of access to high-performance devices.Finally, the paper verifies the data migration algorithm in Disksim simulator. We compare data migration control policies based on MSDV and Cache replacement migration algorithm(LRU、LFU、LRU-K and LFU-Aging). We proved the efficiency of MSDV in this way.