Transfer Rates for bbcp

100MB files were transfered from SLAC (bbr-test-xfer1) to RAL (csfmove01) using bbcp. Different values for the number of streams and window sizes were tested.

• Three different window sizes were used: 128k, 512k and 1M
• Six different values for the number of streams were used: 5,10,15,20,20 and 40
• Each transfer was done twice.
• The total number of transfers per test was 3*6*2 = 24
• The order of the transfers were randomly chosen.
• Twenty 100 MB files were transfered from SLAC.
• The file, window size and number of streams were chosen randomly from the available values.
• For each set of parameters two transfers were performed.
• bbcp were started from the target (RAL) site.
• The bbcp command and the respective output is:

  > bbcp -v -s -w bbr-test-xfer01:/ddist/wilko/test100M /dev/null File /dev/null/test100M created; 104857600 bytes at 10511.2 KB/s 1 file copied at effectively 8749.9 KB/s

• The transfer rate used is the one from the "File ... bytes at XXX KB/s" line.
• The effective rate is usually lower due to some overhead for initiating the ssh connections and starting the bbcp processes. Between SLAC and RAL the overhead is about 3.5s .