中文摘要：

基于闪存的固态硬盘（Solid State Driver，SSD）已成为目前广泛使用的一种持久存储设备．但是由于闪存不对称的I／O特性以及价格因素，SSD还不能完全取代传统硬盘（Hard Disk Driver，HDD）．因此，由SSD和HDD组成的混合存储系统逐步成为目前研究的重点．文中针对SSD和HDD混合存储问题，提出了一个时间敏感的混合存储模型用来有效地利用SSD．该模型把SSD和HDD作为同级的存储设备，结合数据页的访问次数以及访问热度实现对页面的准确分类和分配，即将读倾向负载的hot页面分配到SSD存储，写倾向负载的页面或者cold页面分配到HDD存储，从而利用SSD和HDD不对称的I／O特性来降低系统总的I／O延迟．作者分别在基于高端SSD和中端SSD的混合存储系统上实现了提出的混合存储模型，并进行了性能评测．实验结果显示，作者提出的模型可以实现对数据页更准确的分类，可以有效地降低页面迁移代价，在较少的SSD存储条件下取得了显著的性能提升．

英文摘要：

Solid state driver widely used. But it can not （SSD） based on flash memory has become a persistent storage device take place the magnetic disks absolutely due to the imbalance I/O character and the high price of flash memory. The hybrid storage system consisted of SSD and HDD is gradually becoming the research issue. For the hybrid storage with SSD and HDD, this paper proposes a time-sensitive hybrid storage model to efficiently take use of SSD. This model takes SSD and HDD at the same level of the memory hierarchy. According to the page access counter and access temperature, the model achieves accurate page classification and placement which places the hot and read-intensive pages SSD and places the cold or write-intensive pages to HDD. So the model takes advantage of the asymmetric I/O properties of HDD and SSD to reduce total I/O latency of system. We separately realizes the model on the hybrid storage based on high-end SSD and middle-end SSD and finish the performance evaluation. The experimental result shows that our model can achieve more accurate page classification, reduce the migration cost and get obvious performance improvement with fewer SSD.