Synchronous independent write cache: a novel SSD-aware write cache for RAID

Flash memory has lately been used in order to create robust storage systems over hard disk drives as they offer better performance including better reliability and durability. Although HDD's are economical, they are increasingly incompetent to meet high I/O performance requirements. Flash memory based SSD RAID has an excellent I/O performance making it get more and more attentions from manufacturers. However SSD's have a higher overload in the process of garbage collection. To mitigate this problem, the internal write cache can be used. Still, the state-of-the-art write caches for RAID controller are not designed to handle performance variability. In this thesis, I have analyzed the most recent RAID caches and Interface based RAID implementations that proves less GC overhead and have proposed synchronous independent write cache algorithm. The simulations show up to 71% and 64% improvement in average response time on RAID-0 and RAID-5 respectively when compared with the most recent RAID cache and a much closer performance compared with interface based implementations without the cost of having a separate interface.