XRootD Buffer

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UNDER CONSTRUCTION

General Design

  • A few bits of info:
    • 230MB per readout (all 6 APAs, 5ms window)
    • Lossless compression: 4
    • File size will determine the number of parallel writes and vice versa
    • Nominal "max top instantaneous rate": 3GB/s
    • Nominal spill is 4.5s
    • Spill cycle: 22.5s
    • Nominal data in spill: 13.5GB
    • Nominal data out of spill: 13.5GB
    • Average sustained: 1.2GB/s
  • A proposal for the online buffer:DUNE DocDB 1628

XROOTD-FTS Interface

Design Considerations

  • ofs.notify can be set to send ASCII messages to a FIFO or a user app/script
  • format and content of the message can be configured by the developer
  • considerations for blocking of xrootd by the reader of the FIFO

Functionality

  • Receive a notification and parse it
  • Run a part or all of the metadata generation, write it to a JSON file
  • Send a HTTP post to the F-FTS agent