Improving File Fetches in AFS

Abstract

We describe two enhancements to the AFS distributed file system intended to improve the performance of large file fetches over high-speed networks. Selective caching AFS bypasses the client local disk when fetching files, which improves the performance of applications such as streaming video, for which local caching is of little benefit, and gives client processor and cache resources to applications for which local caching is an advantage. Split-path AFS augments the conventional UDP-based connection between AFS client and server with a "fast path" over native ATM AAL5 for file data fetches.These enhancements combine to reduce the elapsed time of large (100 MB) file fetches by 80% in our laboratory environment. The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other documentation. We describe two enhancements to the AFS distributed file system designed to improve the performance of large file fetches over high-speed networks. Selective caching AFS bypasses the client local disk when fetching files, which improves the performance of applications such as streaming video, for which local caching is of little benefit, and gives client processor and cache resources to applications for which local caching is an advantage. Split-path AFS augments the conventional UDP-based connection between AFS client and server with a "fast path" over native ATM AAL5 for file data fetches.These enhancements combine to reduce the elapased time of large (100 MB) file fetches by 80% in our laboratory environment.