Removing the costs and retaining the benefits of flash-based SSD virtualization with FSDV

We present the design, implementation, and evaluation of the File System De-Virtualizer (FSDV), a system that dynamically removes a layer of indirection common in modern storage stacks and decreases indirection space and performance costs. FSDV is a flexible, light-weight tool that de-virtualizes data by changing file system pointers to use device physical addresses. When FSDV is not running, the file system and the device both maintain their virtualization layers and perform normal I/O operations. We implement FSDV with ext3 and an emulated flash-based SSD. Our evaluation results show that FSDV can significantly reduce indirection mapping table space in a dynamic way while preserving the foreground I/O performance. We also demonstrate that FSDV only requires small changes to existing storage systems.