<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Kostas Magoutis</style></author><author><style face="normal" font="default" size="100%">Salimah Addetia</style></author><author><style face="normal" font="default" size="100%">Alexandra Fedorova</style></author><author><style face="normal" font="default" size="100%">Margo I. Seltzer</style></author><author><style face="normal" font="default" size="100%">Jeffrey S. Chase</style></author><author><style face="normal" font="default" size="100%">Andrew J. Gallatin</style></author><author><style face="normal" font="default" size="100%">Richard Kisley</style></author><author><style face="normal" font="default" size="100%">Rajiv G. Wickremesinghe</style></author><author><style face="normal" font="default" size="100%">Eran Gabber</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Structure and Performance of the Direct Access File System</style></title><secondary-title><style face="normal" font="default" size="100%">2002 USENIX Annual Technical Conference</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">dafs</style></keyword><keyword><style  face="normal" font="default" size="100%">distrib</style></keyword><keyword><style  face="normal" font="default" size="100%">filesystems</style></keyword><keyword><style  face="normal" font="default" size="100%">networks</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">June 2002</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.eecs.harvard.edu/syrah/papers/usenix-02-dafs/</style></url></web-urls></urls><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;
The Direct Access File System (DAFS) is an emerging industrial standard for network-attached storage. DAFS takes advantage of new user-level network interface standards. This enables a user-level file system structure in which client-side functionality for remote data access resides in a library rather than in the kernel. This structure addresses longstanding performance problems stemming from weak integration of buffering layers in the network transport, kernel-based file systems and applications. The benefits of this architecture include lightweight, portable and asynchronous access to network storage and improved application control over data movement, caching and prefetching.
&lt;/p&gt;&lt;p&gt;
This paper explores the fundamental performance characteristics of a user-level file system structure based on DAFS. It presents
experimental results from an open-source DAFS prototype and compares its performance to a kernel-based NFS implementation optimized for zero-copy data transfer. The results show that both systems can deliver file access throughput in excess of 100 MB/s, saturating network links with similar raw bandwidth. Lower client overhead in the DAFS configuration can improve application performance by up to 40% over optimized NFS when application processing and I/O demands are well-balanced.
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