A novel approach for mass storage data custodial

Abstract

The mass storage challenge for the Large Hadron Collider (LHC) experiments is still nowadays a critical issue for the various Tier-1 computing centres and the Tier-0 centre involved in the custodial and analysis of the data produced by the experiments. In particular, the requirements for the tape mass storage systems are quite strong, amounting to several PetaBytes of data that should be available for near-line access at any time. Besides the solutions already widely employed by the High Energy Physics community so far, an interesting new option showed up recently. It is based on the interaction between the General Parallel File System (GPFS) and the Tivoli Storage Manager (TSM) by IBM. The new features introduced in GPFS version 3.2 allow to inteface GPFS with tape storage managers. We implemented such an interface for TSM, and performed various performance studies on a pre-production system. Together with the StoRM SRM interface, developed as a joint collaboration between INFN-CNAF and ICTP-Trieste, this solution can fulfill all the requirements of a Tier-1 WLCG centre. The first StoRM-GPFS-TSM based system has now entered its production phase at CNAF, presently adopted by the LHCb experiment. We will describe the implementation of the interface and the prototype test-bed, and we will discuss the results of some tests.