See the relevant discussion on hypernews
bbcp is much faster than scp (~15 MB/s compare to ~0.3 MB/s), but bbcp is not installed at CERN.
Copy it from SLAC (/usr/local/bin/bbcp) to your own CERN area (in my xrootd directory in the following examples):
scp /usr/local/bin/bbcp lxplus.cern.ch:xrootd/bbcp |
Note, you can find the Mac binary at /afs/slac.stanford.edu/package/bbcp/prod/bin/ppc_darwin_80/bbcp
To transfer a single file from CERN to SLAC:
~/xrootd/bbcp -s 64 -P 2 -f notes.txt grenier@noric09.slac.stanford.edu: |
To transfer a whole directory:
~/xrootd/bbcp -s 64 -P 2 -f -r data grenier@noric09.slac.stanford.edu:atlasdata |
To transfer from SLAC to CERN:
~/xrootd/bbcp -z -T /usr/local/bin/bbcp -s 64 -P 2 -f grenier@noric09.slac.stanford.edu:notes.txt notes.txt |
1. bbcp uses ssh. So one can avoid typing password by adding your CERN ssh public key to SLAC's authorized key file (~/.ssh/authorized_keys)
2. I am using 64 streams, which is the maximum.
3. -P 2 is not necessary unless you want to see the process bar.
The number of "optimal" streams varies, and is influenced by the size of the tcp buffers. More streams can actually hurt performance.
There are some tuning suggestion available at: http://pcbunn.cithep.caltech.edu/bbcp/using_bbcp.htm
Usually the default number of streams of ~4 is reasonable, but you want to increase the window size(i.e. eliminate the '-s 64' and instead add in '-w 2M').
Once you have the files at CERN (probably on pcphuat27), you can also put them to/from CASTOR.
https://twiki.cern.ch/twiki/bin/view/Atlas/CastorPools
For instance, to copy a whole directory on pcphuat27 into my castor area (you need an area with write permission!):
xrdcp /u1/ahaas/Zmumu/ root://castoratlas//castor/cern.ch/atlas/atlascerngroupdisk/proj-sit/pileup/ahaas/ |