Redise Flash (RF) offers users of Redise Pack and Redise Cloud Private the unique ability to operate a Redis database that spans both RAM and flash memory (SSD), but remains separate from Redise Pack’s persistence mechanisms. Whilst keys are always stored in RAM, RF intelligently manages the location of their values (RAM vs Flash) in the database via a LRU-based (least-recently-used) mechanism. Hot values will be in RAM and infrequently used, while warm values will be ejected to flash memory. This enables you to have much larger datasets with RAM-like latency and performance, but at dramatically lower cost than an all-RAM database.
Just like all-RAM databases, RF is compatible with existing Redis applications. Databases that employ Redise Flash are identical to all-RAM Redise Pack databases in characteristics and features.
Of your dataset, perhaps there is a subset of highly active objects considered the application’s “working set.” Redise Flash will intelligently manage the location of the working set (RAM) and the infrequently accessed keys (flash memory), based on LRU (least-recently-used). By using Redise Flash to distribute the data between RAM and flash memory, which is much cheaper than RAM, you can lower your TCO and better utilize hardware, hypervisor, and cloud resources. In many cases, Redise Flash can cut resource costs by over 70% when compared to an all-RAM Redise Pack deployment.
With Redise Flash, you can easily configure the ratio of RAM-to-Flash at runtime for each database independently, optimizing performance for your specific use case. Think of this like a gas pedal in a car, the database speeds up as you give it more gas (RAM). We recommend you keep at least 20% of the database in RAM.
When Redise Flash is enabled, additional settings and metrics are available in the system.
To create Redise Flash databases you must meet the following prerequisites:
- Have ephemeral, persistent and flash memory mounted on Redise Pack nodes with the proper disk size, per the Redise Flash memory guidelines.
- Have all software and hardware requirements in place.
- Perform the initial setup and creation of a new cluster.
- Purchase a subscription that supports Redise Flash.
Once these requirements are met, both Redise Flash databases and all-RAM databases can be created and managed in the same cluster. For additional details, refer to Creating a new database.