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Unformatted text preview: In Proceedings of the 2008 USENIX Annual Technical Conference (USENIX08) , Boston, Massachusetts, June 2008 Adaptive File Transfers for Diverse Environments Himabindu Pucha * , Michael Kaminsky , David G. Andersen * , and Michael A. Kozuch * Carnegie Mellon University and Intel Research Pittsburgh Abstract This paper presents dsync , a file transfer system that can dynamically adapt to a wide variety of environments. While many transfer systems work well in their special- ized context, their performance comes at the cost of gen- erality, and they perform poorly when used elsewhere. In contrast, dsync adapts to its environment by intelligently determining which of its available resources is the best to use at any given time. The resources dsync can draw from include the sender, the local disk, and network peers. While combining these resources may appear easy, in practice it is difficult because these resources may have widely different performance or contend with each other. In particular, the paper presents a novel mechanism that enables dsync to aggressively search the receivers local disk for useful data without interfering with concurrent network transfers. Our evaluation on several workloads in various network environments shows that dsync outper- forms existing systems by a factor of 1.4 to 5 in one-to-one and one-to-many transfers. 1 Introduction File transfer is a nearly universal concern among com- puter users. Home users download software updates and upload backup images (or delta images), researchers of- ten distribute files or file trees to a number of machines (e.g. conducting experiments on PlanetLab), and enter- prise users often distribute software packages to cluster or client machines. Consequently, a number of techniques have been proposed to address file transfer, including simple direct mechanisms such as FTP, swarming peer- to-peer systems such as BitTorrent , and tools such as rsync  that attempt to transfer only the small delta needed to re-create a file at the receiver. Unfortunately, these systems fail to deliver optimal per- formance due to two related problems. First, the solutions typically focus on one particular resource strategy to the exclusion of others. For example, rsync s delta approach will accelerate transfers in low-bandwidth environments when a previous version of the file exists in the current directory, but not when a useful version exists in a sib- ling directory or, e.g., /tmp . Second, existing solutions typically do not adapt to unexpected environments. As an example, rsync , by default, always inspects previous file versions to accelerate the transfereven on fast networks when such inspections contend with the write portion of the transfer and degrade overall performance....
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This note was uploaded on 11/12/2011 for the course CE 726 taught by Professor Staf during the Spring '11 term at SUNY Buffalo.
- Spring '11