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Sidebar : Futures and Resources

Enterprise File System

HP may be going off into another direction. In April 1997, HP announced their own distributed filesystem called Enterprise File System (EFS), based on DCE's Distributed File System (DFS version 1.2.1). DFS comes from the Andrew File System by Transarc and offers high availability due to replication, improved performance due to sophisticated client-based caching, and distributed administration.

WebNFS

The idea for Web-based NFS comes from Sun MicroSystems. WebNFS is a complete filesystem, supporting in-place editing of files with preservation of the integrity of shared files. As an example of more efficient utilization of bandwidth, applications can query WebNFS for information about remote file and directory attributes. Currently, to see if a file has changed since the last time it was accessed, you must download or read the entire file. With WebNFS, the application can take advantage of file attributes such as file size and modification date to determine whether a file has been updated, reducing redundant file downloads.

A distributed file is referenced using the following syntax example: nfs://server/project/myfile. WebNFS also supports both NFS 2.0 and NFS 3.0.

Samba

A possible alternative to NFS on PCs is one of the incarnations of Samba, either a commercial or the freeware version from Australia. Samba is a package that runs on a UNIX host (file server). It speaks SMB protocol appearing to the PCs as a LAN Manager server. By use of configuration files on the UNIX host, you can perform a "network connect" to a particular subdirectory and have it appear on your PC as an additional drive letter (such as "E:").

Sys Admin recently had an excellent article about Samba. One performance benchmark shows Samba being equal to or exceeding all competing PC NFS client packages. Samba is worth investigating as a possible distributed file access solution.

References

RFC-1094 NFS: Network File System Protocol Specification
RFC-1813 NFS Version 3 Protocol Specification
RFC-2054 WebNFS Client Specification
RFC-2055 WebNFS Server Specification
NFS Client/Server Configuration; Topology and Performance Tuning Guide. This document can be found on all HP-UX systems in the /usr/share/docs subdirectory.

System Performance Tuning, Mike Loukides. O'Reilly & Associates

Sun Performance and Tuning, Adrian Cockcroft. Prentice Hall

AIX Performance Tuning, Frank Waters. Prentice Hall