Technical aspects

The ESMs account: In case of the presence of a shared file system the ESMs of a VO have to be the only ones to have write access to the experiments space.
This is done by using VO groups. A VO Manager creates the software administration group. The people belonging to this group will be mapped into the local grid-mapfile on all sites to a special local VO software administrative account (for instance, cmsswadm). This account belongs to the local group associated to this VO (for instance, cms). This is required to realize the desired file access authorization. The shared space will be owned by the local VO software administrative account and will be group readable by the VO group (for instance: cmsswadm:cms). The mapping of multiple ESMs to one local account doesn't create a traceability problem for auditing since the logging of the mapping between the ESM's subject and the job id in the gatekeeper guarantees to separate the actions of different ESMs of the same VO. Space management in the shared area: There is none. We assume that the sites provide sufficient space for the experiments to have several versions available (50-100GB). The ESM should check if there sufficient space and remove old versions if needed. For local installation ("." case) the install scripts have to verify that the scratch space is sufficiently large for the software to be installed AND the expected data produced by the job.