Panache: a parallel WAN cache for clustered filesystems.

Panache is a scalable, high-performance, remote file data caching solution integrated with the GPFS cluster file system. It leverages the inherent scalability of GPFS to provide a multi-node, consistent cache of data exported by a remote file system cluster. Panache exploits the soon-to-be standard pNFS protocol to move data in parallel from the remote file cluster. Furthermore, it provides a POSIX compliant file system interface making the cache completely transparent to applications. Panache can mask the fluctuating wide-area-network latencies and outages by supporting asynchronous and disconnected-mode operations. It allows concurrent updates to be made at the cache and at the remote cluster and synchronizes them by using conflict detection techniques to flag and handle conflicts. To maintain commercial viability, Panache relies on open standards for high-performance file serving and does not require any proprietary hardware or software to be deployed at the remote cluster. In this paper we present the overall architecture of Panache and its key features.