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Writing files locally

When writing files locally, that is by using DiskWR, the files are not managed centrally by the Run Database. You are yourself responsible for managing these files. We provide an area for such files, which is mounted on all farm-nodes under /data. There is a group-writable subdirectory for every sub-detector.

These files are regulary (every hour) copied to CASTOR. You will find them there under

/castor/<group name>/


  • small files (< 1 MB) will not be copied to CASTOR - pack them into archives
  • files which are marked as migrated in CASTOR (a small m in the nsls output) can and will eventually be deleted from the Online storage. We never delete files from CASTOR
  • Our scripts are paranoid - if after a file has been copied to CASTOR, you change the size of the file (rewrite, truncate, etc...) - the new file will not be copied and the original file on CASTOR will never be overwritten. Use a new file-name
  • It's ok to create directories on the
    /data/group name>/
    area, they will be recursively copied

-- NikoNeufeld - 03 Jul 2007

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Topic revision: r1 - 2007-07-03 - NikoNeufeld
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