An efficient cache management scheme for capacitor equipped solid state drives

Within SSDs, random access memory (RAM) has been adopted as cache inside controller for achieving better performance. However, due to the volatility characteristic of RAM, data loss may happen when sudden power interrupts. To solve this issue, capacitor has been equipped inside emerging SSDs as interim supplier. However, the aging issue of capacitor will result in capacitance decreases over time. Once the remaining capacitance is not able to write all dirty pages in the cache back to flash memory, data loss may happen. In order to solve the above issue, an efficient cache management scheme for capacitor equipped SSDs is proposed in this work. The basic idea of the scheme is to bound the number of dirty pages in cache within the capability of the capacitor. Simulation results show that the proposed scheme achieves encourage improvement on lifetime and performance while power interruption induced data loss is avoided.