Glossary

CTA technical terms

Virtual Organization:

A grouping of users working with the same data/experiment. As an example, for CTA at CERN each LHC experiment (ATLAS, …), as well as small and medium sized experiments (AMS, NA62, …), is assigned to a dedicated VO with the same name. VOs are used to enforce quotas, such as an experiment’s number of dedicated drives, as well as to gather usage statistics and summaries for each experiments.

Disk Instance:

A different term for “EOSCTA instance”, the ‘small EOS’ instance used to archive/retrieve files from tape. A Disk Instance can have one or multiple VOs assigned to it. At CERN we have created a dedicated Disk Instance for each of the large LHC experiments (eosctaatlas, …) , in addition to instances shared by the small/medium sized experiments (eosctapublic, eosctapublicdisk), based on their archival needs.