The first production version of the CERN Tape Archive (CTA) software is planned to be released for the end of 2018. CTA is designed to replace CASTOR as the CERN tape archive solution, in order to face scalability and performance challenges arriving with LHC Run-3.
This contribution will describe the main commonalities and differences of CTA with CASTOR. We outline the functional enhancements and integration steps required to add the CTA tape back-end to an EOS disk storage system. We present and discuss the different deployment and migration scenarios for replacing the five CASTOR instances at CERN, including a description of how FTS will interface with EOS and CTA.