TFile for dcache Root file via srm?

I can copy a file from our Tier2 dcache to a local disk by first issuing a voms-proxy-init command, and then using srmcp to copy the file.

But can I open a TFile directly using the srm protocol, so avoiding the copy?

Does Root support something like:

TFile(“srm://cit-se.ultralight.org:8443/srm/managerv2?SFN=/pnfs/ultralight.org/data/store/data/BeamCommissioning08/BeamHalo/RAW/v1/000/062/399/FAC7D166-1183-DD11-8B4C-000423D98B6C.root”);

Julian

[quote=“jjbunn”]I can copy a file from our Tier2 dcache to a local disk by first issuing a voms-proxy-init command, and then using srmcp to copy the file.

But can I open a TFile directly using the srm protocol, so avoiding the copy?

Does Root support something like:

TFile(“srm://cit-se.ultralight.org:8443/srm/managerv2?SFN=/pnfs/ultralight.org/data/store/data/BeamCommissioning08/BeamHalo/RAW/v1/000/062/399/FAC7D166-1183-DD11-8B4C-000423D98B6C.root”);

Julian[/quote]
I would try the following:

  • you could set up an XROOTD door on your dCache and then use TFile to access you files normally.
    -also, you could try to use TGFALFile (/io/gfal). I didn’t check this interface, but it suppose to use GFAL.

hi,
i am facing the same problem. I would like to open directly in ROOT some file like e.g.:
srm://clrlcgse01.in2p3.fr:8446/srm/mana … .pool.root
could you point me to some documentation on how to install the GFAL client? (i browsed with the search engine and could not find relevant documentation.
thanks.

Hi,

To build the GFAL plugin you have to configure ROOT with

--enable-gfal --with-gfal-incdir=<path_with_gfal_api.h>  --gfal-libdir=<path_with_libgfal>

After a successful compilation you should have libGFAL.so among the ROOT plugins.

To trigger the plug-in you must prepend your URLs with “gfal:”, e.g.

f = TFile::Open("gfal:srm://clrlcgse01.in2p3.fr:8446/srm/managerv2?SFN=/dpm/in2p3....")

G. Ganis

thanks for the prompt reply. i need to install GFAL in addition. could you point me to the repository? as i said, i could not find it so far.
thanks.

GFAL is installed under AFS at

/afs/cern.ch/sw/lcg/external/Grid/gfal/

which is what is used by the LCG_xx releases.

Sorry, I do not know the location of the source repository, assuming that it is accessible .

G. Ganis

hi,
i finally copied the GFAL .tar.gz from the AFS directory you pointed me to.
i need to configure root again, but need to stick to the LCG settings for building it.
can someone tell me what are the parameters for the configure command used for building the LCG ROOT?
thanks, nabil

sorry for the noise. i already got an answer from ATLAS.
cat /afs/cern.ch/sw/lcg/external/root/5.18.00f/slc4_ia32_gcc34/_SPI/config.status
showing that it is built with GFAL enabled.
thanks.