CERN Tape Archive Run 3 Production Experience CTA Tier-0 service performance during the start of the LHC Run 3 and the various lessons learnt

Abstract

The EOS disk + CERN Tape Archive (EOSCTA) service is CERN’s primary physics data long-term storage and archival solution for LHC Run 3. It entered production at CERN during summer 2020 and has since been serving all the LHC and non-LHC workflows involving archival to-and retrieval from tape. The CTA system is a complete redesign of the previous tape software, tape cache and tape workflows, which will need to scale to the data rate requirements of the present LHC activity period, as well as the one after. At the time of writing it has already set new records for monthly tape archival volume at CERN and reached write efficiencies equalling those demonstrated during earlier data challenges.