CaSSanDra: An SSD boosted key-value store

With the ever growing size and complexity of enterprise systems there is a pressing need for more detailed application performance management. Due to the high data rates, traditional database technology cannot sustain the required performance. Alternatives are the more lightweight and, thus, more performant key-value stores. However, these systems tend to sacrifice read performance in order to obtain the desired write throughput by avoiding random disk access in favor of fast sequential accesses. With the advent of SSDs, built upon the philosophy of no moving parts, the boundary between sequential vs. random access is now becoming blurred. This provides a unique opportunity to extend the storage memory hierarchy using SSDs in key-value stores. In this paper, we extensively evaluate the benefits of using SSDs in commercialized key-value stores. In particular, we investigate the performance of hybrid SSD-HDD systems and demonstrate the benefits of our SSD caching and our novel dynamic schema model.