Sep 2 – 9, 2007
Victoria, Canada
Europe/Zurich timezone
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Using Parrot to access the CDF software on LCG Grid sites

Sep 5, 2007, 8:00 AM
10h 10m
Victoria, Canada

Victoria, Canada

Board: 20
poster Distributed data analysis and information management Poster 2

Speaker

Dr Gabriele Compostella (University Of Trento INFN Padova)

Description

When the CDF experiment was developing its software infrastructure, most computing was done on dedicated clusters. As a result, libraries, configuration files, and large executable were deployed over a shared file system. As CDF started to move into the Grid world, the assumption of having a shared file system showed its limits. In a widely distributed computing model, such as the Grid, the CDF software will be not available natively on each worker node. In order to overcome this problems CDF investigated several solutions and finally Parrot was adopted by LcgCAF, the CDF portal to the LCG Grid resources. Parrot is a virtual filesystem for performing POSIX-like I/O on remote data services. It supports several protocols, including HTTP, FTP, RFIO, and other protocols common in Grid computing. CDF has chosen to use the HTTP protocol, since it can be easily cached by Squid caches, already deployed at, or close to big Grid sites. The current configuration used by CDF in production on LCG sites will be presented together with the different performance benchmarks, both with and without a local Squid. The experience and problems found by using Parrot in a system with several hundred of concurrent users will be discussed. Finally, the problem of cache coherence due to daily code updates will be analyzed and the possible solutions discussed

Primary authors

Mr Aureliano Rama (INFN of Padova) Dr Donatella Lucchesi (University and INFN Padova) Prof. Douglas Thain (University of Notre Dame) Dr Gabriele Compostella (University Of Trento INFN Padova) Dr Igor Sfiligoi (Fermilab) Dr Simone Pagan Griso (University and INFN Padova)

Presentation materials

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