BaBar中的分布式离线数据重构
Distributed Offline Data Reconstruction in BaBar
摘要：
SLAC的BaBar实验已经进入第四个年头。数据处理系统一直在不断发展，以应对更高光度运行和每年重新处理的数据量不断增加的挑战。为了实现这些目标，采用了双通道处理架构，其中在第一通道中对一小部分事件快速计算“滚动校准”，并在第二通道中进行批量数据重建。这允许在第一次通过中的快速检测器反馈，并允许在两个或更多个单独的农场上并行化第二次通过。这种双通道系统还允许将加工农场分布在场外。第一个这样的网站已经在INFN帕多瓦建立。这里遇到的挑战很多。该软件被移植到一个完整的基于Linux的商用硬件系统上。原始数据集（90 TB）是使用155 Mbps网络链接从SLAC导入的。开发了一个质量控制系统，并将处理后的数据输出回SLAC。在SLAC和Padova之间，我们目前运行着三个一次通过的场，每个场有32个CPU，九个二次通过的场，每个场有64到80个CPU。两个场每天可以处理200万到400万个事件。将介绍有关该系统的实施和性能的详细信息。
英文摘要：
The BaBar experiment at SLAC is in its fourth year of running. The data processing system has been continuously evolving to meet the challenges of higher luminosity running and the increasing bulk of data to re-process each year. To meet these goals a two-pass processing architecture has been adopted, where 'rolling calibrations' are quickly calculated on a small fraction of the events in the first pass and the bulk data reconstruction done in the second. This allows for quick detector feedback in the first pass and allows for the parallelization of the second pass over two or more separate farms. This two-pass system allows also for distribution of processing farms off-site. The first such site has been setup at INFN Padova. The challenges met here were many. The software was ported to a full Linux-based, commodity hardware system. The raw dataset, 90 TB, was imported from SLAC utilizing a 155 Mbps network link. A system for quality control and export of the processed data back to SLAC was developed. Between SLAC and Padova we are currently running three pass-one farms, with 32 CPUs each, and nine pass-two farms with 64 to 80 CPUs each. The pass-two farms can process between 2 and 4 million events per day. Details about the implementation and performance of the system will be presented.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
