Redis on Flash
Redis Enterprise allows for creation of Redis on Flash (RoF) databases that extend your DRAM capacity with SSD and persistent memory to store significantly more data with fewer resources, reducing costs. Redis on Flash is not designed to be used as an alternative mechanism for data persistence—the same AOF and snapshot data-persistence mechanisms are used with Redis on Flash. RoF is based on the core open-source Redis architecture with some primary enhancements:
Instead of keeping the entire dataset in DRAM, RoF keeps only the keys and the Redis dictionary (the data structure behind the keys) in DRAM, along with the “hot values” of the dataset (the working set). The “warm values,” the lesser-used portion of the dataset, are kept on the local Flash storage.
To avoid head-of-the line blocking scenarios resulting from the single-threaded nature of Redis, RoF is based on a multi-threaded asynchronous architecture that guarantees no blocking between a heavy request made to Flash and a light request made to DRAM.
This multi-layer memory architecture is shown here:
