Aerie: flexible file-system interfaces to storage-class memory

Storage-class memory technologies such as phase-change memory and memristors present a radically different interface to storage than existing block devices. As a result, they provide a unique opportunity to re-examine storage architectures. We find that the existing kernel-based stack of components, well suited for disks, unnecessarily limits the design and implementation of file systems for this new technology. We present Aerie, a flexible file-system architecture that exposes storage-class memory to user-mode programs so they can access files without kernel interaction. Aerie can implement a generic POSIX-like file system with performance similar to or better than a kernel implementation. The main benefit of Aerie, though, comes from enabling applications to optimize the file system interface. We demonstrate a specialized file system that reduces a hierarchical file system abstraction to a key/value store with fewer consistency guarantees but 20-109% higher performance than a kernel file system.