Lowering the Number of Live-Page Copies on Solid State Drives through Trim-Assisted Space Allocation

Due to the inherent limitations of solid state drives (SSDs), the garbage collection policy is a performance-critical design within the flash translation layer (FTL), designed to manage the internal limitations of SSDs and emulate the functionalities of conventional storage devices. To assist garbage collection, the concept of trim command has been designed and deployed by marking storage space as invalid and reducing the number of live-page copies during garbage collection. Nevertheless, conventional approaches usually utilize trim information during garbage collection, and the possibility of utilizing trim information during data allocation receives much less attention. Such an observation motivates this paper to propose a trim-assisted space allocation mechanism to lower the number of live-page copies from the source where the invalid space is produced. The experiments show promising results.