CERN (European Organization for Nuclear Research) is one of the world's largest and most respected centres for scientific research. It is home to the world's largest particle accelerator (Large Hadron Collider, LHC) and is the birthplace of the Web.

CERN's Storage and Data Management Group is responsible for enabling data storage and access for the CERN laboratory, in particular the long-term archival, preservation and distribution of LHC data to a worldwide scientific community (WLCG).

The CERN Tape Archive (CTA) Service manages more than 900 PBs of data distributes over about 50,000 high-capacity tapes in 6 tape libraries. The service ingests this exponentially growing amount of data at LHC data acquisition rates though its EOS based flash buffer and feeds up to 180 tape drives that write date on mounted tapes at over 90% write efficiency.

This high efficiency archival service runs on open-source software and is deployed on-premise on commodity hardware.

In this talk I would like to give you a high level view of the global CERN tape service performances and dive in the details of its real life deployment: from the flash buffer design principles to the tape servers connected to multiple tape drives via a dedicated network topology.

All of the presented software are open source and available for use and are deployed in other laboratories around the world.