Accessing data / Notes on data management

The beamlines at PETRA III provide storage space during beamtime by the Online Fileserver or dedicated local disc buffers (e.g. Perkin Elmer PCs). Both ensure beamline operation and should allow for analyzing data during the beamtime. This kind of storage is not a permanent storage and has to be cleaned up in a regular manner.

In general, the users copy their data during the beamtime to own disc space. Given an appropriate moment, user data is migrated to dCache (by default, experiment data is migrated to traditional dCache with tape back end as single or multiple tarballs).

The migration offers the possibility to get access to data past the experiment, either for downloading (typically external users) or analysis (typically DESY FS staff). It ensures the existence of an archive copy of the measured data and allows to free storage space on the Online Fileserver.