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Photon Science Data are stored in the DESY computer center. The page ASAP3 Data Storage for PETRA III contains lots of information. This chapter contains an excerpt with the most important information.

Data are stored on two GPFS servers: the Beamline and the Core file systems.


  • GPFS Beamline FS
    • The FS is visible from experiment PCs (ExpPC) and detector PCs (DetPC).
    • Files can be created by beamline, e.g. p01user, and detector accounts, e.g. det.
    • Unix authorization applies. Therefore, to store detector images, the beamline user creates the parent directory and sets the permissions to 777.
    • The FS has no ACLs.


  • GPFS Core FS
    • The FS is not visible from the ExpPCs and the DetPCs.
    • The FS is accessed with DESY accounts or Science Accounts.
    • It has ACLs being created during the migration process.
    • The inital ACLs are set using DOOR information based on the beamtimeID (DESY accounts, if existing, corresponding to the DOOR accounts given in the Beamtime 'List of participants').
    • The ACLs can be modified by the Beamtime Applicant or Leader via the gamma-portal.
    • The migration process changes the Unix-owner of all raw data to FSDATA:FSDATA.
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