LWPMFS: Light-Weight Persistent Memory Filesystem

Ravi Pokala <rpokala@freebsd.org>

Panasas creates high-capacity, high-performance, high-availability storage appliances. A perennial problem in storage is the tradeoff between performance, which requires aggressive cacheing, and data safety, which requires getting the data onto stable storage as soon as possible. In this context “stable” includes “persistent across power failure”.

The first part of this talk recaps how Panasas originally addressed power-failure safety: an enclosure-wide battery backup, part of our custom hardware and software platform.

The second part of this talk describes how Panasas is addressing power-failure safety in the world of Commercial Off-The-Shelf (COTS) hardware platforms: an NVDIMM, drivers to interface with it, and a persistent-memory-aware filesystem.