ComputingResourcesUserGuide
Brief User Guide to Computing Resources at FLASH
Introduction
As explained in the User overview page the data recorded at FLASH is stored in an internal DAQ format (.raw) which is converted with a few minutes delay to easily accessible HDF5 (The FLASH HDF5 structure) files which are the basis for data analysis. These files are stored on the ASAP3 File System which is accessible from DESYs Maxwell Cluster which is recommended to be used for the analysis by users. A library provided by FLASH ( BeamtimeDaqAccess ) allows efficient access to the recorded data in the HSD5 files. In addition the HDF5 files are accessible from the beamline computers and via a web interface: Gamma Portal
Access to the Maxwell cluster
The Maxwell Cluster is a powerful farm of inter-connected PC nodes running Scientific GNU/Linux. To access the cluster you need a DESY AFS computing account or a so called scientific account (PSX).
- If you have a default DESY AFS account login to max-fsc.desy.de using your personal account. (From outside of DESY network tunnel through bastion.desy.de or use the remote login to max-display.desy.de.
- Scientific account users instead go to desy-ps-cpu.desy.de. To connect to the Maxwell cluster from outside the DESY network -- eduroam or the DESY guest network are considered to be outside -- then you can SSH tunnel your connection through desy-ps-ext.desy.de or more conveniently directly use the remote login to max-display.desy.de.
Note: Please, always do use your personal account to work on the Maxwell cluster or any central DESY computing resources. Don't use the functional accounts like vuvfuser or bl1user. Using functional accounts on shared resources causes many difficult to predict problems, even if it might appear to work for you in the beginning. Also, never try to login to bastion, desy-ps-ext, or max-display using one of the functional accounts.
The rest of this guide assumes you can login to the suggested Maxwell cluster node and are able to successfully run the command xclock to get a clock face displayed on your client computer.