A Bit Operations Replacement Algorithm For FLASHCACHE

Human society has entered information age where the total amount of information increases exponentially. The contradiction of storage system performance, capacity, and cost become increasingly prominent. Multi-tiered storage system as a way to effectively resolve these contradictions technology is concerned by enterprises and academic community. The so-called tiered storage, is using tiered storage software to automatically migrate data objects between the different levels of storage devices. In the recent decade, enterprises and academic community have made multi-tier storage system more automated-based and intelligent and have developed many multi-tier storage systems to meet the demands.FlashCache (an open source software published by Facebook) is a typical multi-tier storage system. And it can significantly improve the storage system's IOPS (I / O per second) performance.In this thesis, we made research about the technology of SSD in multi-tier storage systems based on FlashCache. We designed and implemented a bit operations replacement algorithm. The main work of this thesis includes:1) Study and analyze the design of some current multi-tier storage systems.2) Study the characteristics of SSD and disks, and analyze the differences between them.3) Analyze the design of FlashCache, including the data structure and algorithms, and make evaluation.4) Design the detailed implementation of the bit operations replacement algorithm for FlashCache.Performance test verified that the bit operations replacement algorithm designed and implemented by this thesis can meet the need of multi-tier storage system and the algorithm proposed by this thesis can significantly extend the using life time of SSD. This research is also a valuable reference for other cache algorithm design.