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Hi Fabrizio, you could make the options to xrdcp a bit more friendly. How about: xrdcp -D 8080 root://kanolb-a.slac.stanford.edu//store/SP/R14/000993/run4/14 .4.0c/SP_000993_002423.02E.root ~fabrizio/ -DISocks4Port is a bit long and for the host you can default to the localhost to avoid specifying -DSSocks4Server. Anyway it should be simple to pass these extra options to TXNetFile. Cheers, Fons. Jean-Yves Nief wrote: > Adye, TJ (Tim) wrote: >> Hi Fabrizio, >> >> Yes, this is very interesting. We have been investigating the use of the >> xrootd proxy as another way to access data remotely from SLAC. Using ssh >> seems to have the advantage of not requiring any extra infrastructure, >> but only works for xrdcp (at the moment) and requires specific user >> setup. Anything else? Have you made any performance comparisons? >> > in the ROOT framework, the people who were using the ssh tunnel from > their site made some performances tests compared to local access to the > file (local disk): there was a factor of 2, but of course that includes > not only the tunnelling but also the fact that the access was made from > a distant site. It was considered to be satisfactory for the kind of > applications they were meant to run from a distant site (most of their > processing is made directly from the Lyon batch farm). > JY > >> Thanks, >> Tim. >> >> >>> -----Original Message----- >>> From: [log in to unmask] On Behalf Of Fabrizio >>> Furano >>> Sent: 30 October 2006 14:54 >>> To: Jean-Yves Nief; Brew, CAJ (Chris) >>> Cc: Xrootd Mailing List; Andrew Hanushevsky; Peter Elmer >>> Subject: Ssh tunnels for XrdClient >>> >>> Hi JY and Chris, >>> >>> I remember that, at some point (if I remember correctly) you have >>> been interested in the possibility of communicating with an xrootd >>> server through ssh tunnels. Since this was one of the latest commits, >>> if you want to give a try to it, it's there (in the head). >>> Basically it's an implementation of the SOCKS4 protocol in >>> XrdClient. What follows is an example of how to use it. >>> >>> I suppose that I want to access the file >>> >>> root://kanolb-a.slac.stanford.edu//store/SP/R14/000993/run4/14 >>> .4.0c/SP_000993_002423.02E.root >>> >>> into my laptop in Padova. We know that the kanga cluster at slac is >>> not accessible from outside (at least not from here). Here is a >>> trivial example of how to do it using a SOCKS4 ssh tunnel and xrdcp. >>> >>> Step 1: Tunnel localhost-->noric02 mapping the local port 8080 >>> through SOCKS4 >>> >>> fabrizio@dhcp-61 15:20:32 ~>ssh -D 8080 [log in to unmask] >>> >>> Step 2: in another window... >>> >>> fabrizio@dhcp-61>xrdcp -d 2 -DISocks4Port 8080 -DSSocks4Server >>> 127.0.0.1 root://kanolb-a.slac.stanford.edu//store/SP/R14/000993/run4/14 >>> .4.0c/SP_000993_002423.02E.root ~fabrizio/ >>> >>> and the copy should be ok. >>> ... if you want to shut it up, remove the "-d 2" parameter. >>> Well, from Europe you will note that the data xfer rate is very low. >>> This will hopefully change in December, when we finish implementing >>> the multistream stuff. >>> >>> Please note that the parameter Socks4Server does not understand names >>> yet, but IP addresses only. >>> Another thing that made me crazy. Typically the ssh-tunnelled port >>> (8080 in the example) is only available from localhost. To override >>> this and make it visible also from other hosts, you have to use the >>> "-g" switch (for older ssh) or specify */8080 (in the more recent >>> releases of ssh). >>> >>> Any comment? >>> Fabrizio >>> >>> >>> > -- Org: CERN, European Laboratory for Particle Physics. Mail: 1211 Geneve 23, Switzerland E-Mail: [log in to unmask] Phone: +41 22 7679248 WWW: http://fons.rademakers.org Fax: +41 22 7669640