LHCb Data Management on the Computing Grid

The LHCb detector is one of the four experiments being built to harness the proton-proton collisions provided by the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN). The data rate expected, when the LHC experiments are fully operational, eclipses that of any previous scientific experiments and has motivated the adoption of a grid computing paradigm to store and process the data. Managing PetaBytes of data in a distributed environment provides a rich set of challenges related to scalability, reliability and performance. This thesis will present the data management requirements for executing the workload of the LHCb collab- oration. We present the systems designed that support all aspects of the grid data management for LHCb, from data transfer, to data integrity, and efficient data access. The distributed computing environment is inherently unstable and much focus has been made on providing systems that are ro- bust and resilient to observed failures

Logistical multicast for data distribution

This paper describes a simple scheduling procedure for use in multicast data distribution within a logistical networking infrastructure. The goal of our scheduler is to generate a distribution schedule that will exploit the best network paths by using historic network performance information. A ”spanning tree ” is constructed between available logistical depots to help reduce the overall time of data movement. Our hypothesis is that we can generate appropriate schedules from historical network measurements. In order to evaluate the scheduling procedure we have employed the multicast operation used in the Internet Backplane Protocol (IBP) middleware suite. Investigation into the merits of such a scheduling procedure involved a control group that performs a broadcast to a set of logistical depots and an experimental group that is configured to perform a multicast via schedules generated based on historical network data. All testing was conducted on PlanetLab, a distributed network service testbed.