F-LRU: An efficient buffer replacement algorithm for NAND flash-based databases

In this paper, an efficient buffer replacement algorithm called F-LRU is proposed for NAND flash-based databases. The proposed F-LRU algorithm maintains two Least Recently Used (LRU) page lists, which are a mixed page list and a dirty page list. The proposed F-LRU algorithm improves the buffer hit ratio by first evicting cold clean pages and reduces the number of write operations by giving dirty pages a second chance to stay in the buffer. The proposed F-LRU algorithm can dynamically adjust the lengths of the mixed page list and the dirty page list to adapt to different kinds of NAND flash memory with different cost ratios of write operation to read operation. A series of trace-driven simulations have been conducted on two kinds of NAND flash memory with cost ratios 118:1 and 2:1. Experimental results show that the proposed F-LRU algorithm performs better than the state-of-the-art buffer replacement algorithms in terms of the buffer hit ratio, the number of write operations, and the runtime.