Overcoming Unix kernel deficiencies in a portable, distributed storage system.

摘要

The LINCS Storage System at Lawrence Livermore National Laboratory was designed to provide an efficient, portable, distributed file and directory system capable of running on a variety of hardware platforms, consistent with the IEEE Mass Storage System Reference Model. Our intent was to meet these requirements with a storage system running atop standard, unmodified versions of the Unix operating system. Most of the system components runs as ordinary user processes. However, for those components that were implemented in the kernel to improve performances, Unix presented a number of hurdles. These included the lack of a lightweight tasking facility in the kernel; process-blocked I/O; inefficient data transfer; and the lack of optimized drivers for storage devices. How we overcame these difficulties is the subject of this paper. Ideally, future evolution of Unix by vendors will provide the missing facilities; until then, however, data centers adopting Unix operating systems for large-scale distributed computing will have to provide similar solutions. 11 refs., 5 figs.