The new CERN tape software - Getting ready for total performance

Abstract

CASTOR (the CERN Advanced STORage system) is used to store the custodial copy of all of the physics data collected from the CERN experiments, both past and present. CASTOR is a hierarchical storage management system that has a disk-based front-end and a tape-based back-end. The software responsible for controlling the tape back-end has been redesigned and redeveloped over the last year and was put in production at the beginning of 2015. This paper summarises the motives behind the redesign, describes in detail the redevelopment work and concludes with the short and long-term benefits.