Kolkata Tier-2 Centre: Administration and Installation

Abstract

Grid Computing has been considered as the solution for dealing with large amount of data produced in large experiments like ALICE, STAR etc. Grid comprises of many small sites geographically distributed across the globe. Therefore for this complex system, installation of a Grid site, day to day administration and management of the site and meeting the SLA (Service Level Agreements) and providing QA (Quality Assurance) services are challenging. This article describes Alice Grid as a whole, its architecture, tier based model, jobs of different tiers and procedure of job submission and storage with xrootd. One tier-2 grid computing centre has been installed at VECC-SINP campus in Kolkata, India for ALICE experiment under WLCG (Worldwide LHC Computing Grid). The article describes details of the installation of the Tier-2 site from scratch and bringing it upto the requirement of an experiment and describes, day to day administration and maintenance of the site. The installation procedure includes the discussion on infrastructure, cooling and power supply in addition to the procurement of computing hardware, building cluster, installing middleware as per the requirement of the WLCG and then maintaining software accordingly to the VO (Virtual Organization) requirement (for us ALICE experiment). The administration of the site requires continuous update of OS, middleware with respect to CE, SE, VOBOX and many other related to the security of the site. Apart from maintaining the Grid computing site, administrator has to provide computing infrastructure to the local users with sufficient storage and computing power in terms of a dedicated Tier-3 site. The challenges involved in all the steps related to the grid site will be discussed in this chapter with Kolkata tier-2 centre as a case study. It also explains Kolkata Tier2 connectivity with ALICE and explains Kolkata Tier-2 with its hardware, architecture and middle ware installation in whole for Cream-CE and Pure XrootD Storage.