1. Marco Cattaneo - DTF - 28th February 2001 File sharing requirements of the physics community  Background  General requirements  Visitors  Laptops  Software development and physics analysis  Web services  Summary

2. Background  IT divisional planning report (CERN-IT-DLO-2000-005) “A three person team, composed of representatives from the physics user community, PDP and IS groups should produce a concise document consolidating the existing user requirements for Data Sharing by April 2001” MC, Bernd Panzer-Steindel, Alberto Pace Produce early draft, to gather feedback from DTF and FOCUS.  Draft URD written by M.Cattaneo With input from a few users in a number of experiments and roles Atlas, CMS, LHCb, (Aleph), IT/CO Physicists, Librarians, Software developers, external users Not yet discussed widely in EP and/or FOCUS Not official position of anybody! Not addressing sharing of bulk physics data and “group n-tuples”

3. General requirements Transparent file access from any node on site Interactive and batch, Windows and Unix Same files and directory structure, same access rights, no ‘stale’ files “Native” access to files Use native OS commands, native access to files from applications Customisable protections ACLs for individuals and groups  Modifiable by users, via scriptable tools, at file or directory granularity Groups can be “corporate”, user defined, overlapping Authentication Single site-wide login, remote command execution Transmitted to batch and scheduled jobs Fast and reliable > 99% up time Regular backups (including open files), restore in few minutes Possibility to execute unique site-wide login script With user, group, experiment customisation Source control and versioning

4. Visitors Efficient read/write access to personal files Home institute files from CERN, CERN files from home institute Ideally, the same physical home directory (or mirror)  Not yet possible due to network response  Transparent read/write access to remote directory acceptable alternative Maximum once/day authentication at remote site Technology chosen at CERN should be: Installable also at home labs  At reasonable cost  Ideally as single HEP-wide solution Allow simple porting of scripts and other tools to home-lab file system Allow simple mirroring of selected directories to home-lab file system

5. Laptops Possibility to install authentication and file-sharing software on laptop Access to CERN files when on CERN intranet Access to home-lab files when on home-lab intranet  without major reconfiguration of laptop Automatic synchronisation of selectable sets of files upon connection to CERN intranet Allow laptop user to continue working seamlessly in CERN-like environment when not connected.

6. Software development (including for physics analysis) Requirements for code repository Experiment wide read access from anywhere in the world Write access rights based on individual and/or group identification Requirements for software build and release Highly efficient, native, source code access by build process  Not necessarily shared  But must be possible to install binaries on shared file system Automatic submission of builds on other platforms  And other sites? Access to same files via multiple paths  aka Unix soft links Requirements for release areas Site-wide, native, access to source code and binaries  Compile, link against released software, load shareable libraries at run-time Site-wide access to both general purpose and experiment specific software  On all interactive and batch nodes World-wide access to official release areas  Via world-wide access to CERN file system Especially for “nightly builds” or rapidly evolving software  Via automatic mirroring, or distribution kits World wide access to automatic code documentation

7. Web access Possibility to make any file accessible from web, by simple manipulation Possibility to make any directory accessible from the web With or without directory browsing Possibility to restrict access With similar range of protection categories as for home directories Ideally with same authentication mechanism Possibility to have multiple authors Possibility to maintain web sites remotely i.e. from outside CERN for site hosted at CERN Possibility to edit sites from any platform i.e. from both Windows and Linux Especially important for sites with multiple authors

8. Summary  Site wide, cross platform (Unix/Windows) data sharing  Application transparent file access, including file manipulation with native commands  Access control from all platforms, with authentication based on groups as well as individuals.  Access from outside CERN  Document aggregation (“directories”) to allow sharing of a large number of (small) files as a single object.  Fast and reliable file access  Source control and automated versioning