An Innovative Bridge Layer Access Control Method to Improve SSD Utilization

Due to the characteristics of "erase-before-write" and "page write, block erase", SSDs will perform out-of-place updates. Out-of-place updates will produce a large number of fragmented pages, so the garbage collection process is required. In order to ensure the smooth progress of garbage collection, OP space needs to be set. If the OP space is set too large, the storage resources will be wasted. If the OP space is set too small, the write amplification and block erasure count will be increased, and the lifetime of SSDs will be reduced. To improve the overall utilization of SSDs, an innovative bridge layer access control method is designed. Firstly, the capacity mapping module provides real mapping and virtual mapping to host and operating system respectively, so that smaller OP space can be set and the space utilization of SSDs can be improved. Then, random writes are converted into sequential writes through the write conversion module, so as to reduce the number of block erasures and improve the lifetime of SSDs. Finally, the effectiveness of the proposed bridging layer is proved by experiments.