Towards Application Driven Storage. Optimizing RocksDB for Open-Channel SSDs

Open-channel SSDs enable the host to undertake responsibilities that in typical SSDs are assumed by the Flash Translation Layer (FTL) embedded in the device. From the application perspective, this means that storage policies that have traditionally been based on best efforts can now be tailored for each specific application. In other words, applications can implement their own FTLs and govern data placement and garbage collection.

In this talk at LinuxCon Europe, I explain how to integrate an application FTL with LightNVM – the kernel subsystem providing support for Open-Channel SSDs. More specifically, I report on the design and implementation of a LightNVM backend for RocksDB we refer to as DFlash (Direct Flash). The focus is on both the LightNVM interfaces to which other applications could hook to, and the modifications to RocksDB so that it can communicate with LightNVM. I also provide some experimental results on a real hardware CNEX Labs Open-Channel SSD.

If you have any questions or feedback feel free to write to me at javier<at>

Presentation PDF.

Enjoy! 🙂

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