At CERN there is a service called CERNbox which will provide CERN users with a Cloud storage area. The backend storage for it will be EOS at CERN. It would be obvious that Ganga should implement an interface to CERNbox as a GangaFile that can then be used for input and output. It can be accessed in several different ways:

• Web interface
• Windows and OSX clients (CERN only)
• Any OwnCloud client
• An app for iOS and Android (search for CERNbox)
• As a file system on linux via fuse, wdfs -u [user] -f https://box.cern.ch/remote.php/webdav [mpoint]

Technicalities

CERNbox is still (Sep 2014) a beta service but has large parts of the functionality in place already. It is based on OwnCloud. There are several protocols available for interacting with it. Of interest for Ganga might be

• WebDav access. This is effectively through https. This would be a nice option as it would allow for many other storage areas to use the same technology. ATLAS is already accessing data files throguh this so it should be quite easy to set up the WebDav server to allow x.509 authentication (Grid proxies).
• xrootd access. This would write directly into the EOS backend. Would have the benefit of adding support for writing into any EOS location from Grid jobs. Performance is optimised for large files and can deal with overloaded servers.

Python packages to help

• pyxrootd. Python bindings for xrootd. Relies on the shared libraries of an xrootd installation.
• tinyDav
• pyocclient. Specific client for OpenCloud. Hard to see the advantage of using this.

Contacts

The main contacts at CERN are Kuba Moscicki and Massimo Lamanna.

-- UlrikEgede - 10 Sep 2014