Date Added: Apr 2010
Flash-based Solid State Drives (SSDs) offer superior performance over hard disks for many workloads. A prominent use of SSDs in modern storage systems is to use these devices as a cache in the I/O path. In this paper, the authors examine how transparent, online I/O compression can be used to increase the capacity of SSD-based caches, thus increasing the cost-effectiveness of the system. They present FlaZ, an I/O system that operates at the block-level and is transparent to existing file-systems. To achieve transparent, online compression in the I/O path and maintain high-performance, FlaZ provides support for variable-size blocks, mapping of logical to physical blocks, block allocation, and cleanup.