Global EOS: exploring the 300-ms-latency region

EOS, the CERN open-source distributed disk storage system, provides the highperformance storage solution for HEP analysis and the back-end for various work-flows. Recently EOS became the back-end of CERNBox, the cloud synchronisation service for CERN users. EOS can be used to take advantage of wide-area distributed installations: for the last few years CERN EOS uses a common deployment across two computer centres (Geneva-Meyrin and Budapest-Wigner) about 1,000 km apart (∼20-ms latency) with about 200 PB of disk (JBOD). In late 2015, the CERN-IT Storage group and AARNET (Australia) set-up a challenging R&D; project: a single EOS instance between CERN and AARNET with more than 300ms latency (16,500 km apart). This paper will report about the success in deploy and run a distributed storage system between Europe (Geneva, Budapest), Australia (Melbourne) and later in Asia (ASGC Taipei), allowing different type of data placement and data access across these four sites.