HPSS and xrootd integration

Restoring files from HPSS

Prestage files

The xprep command is used to instruct Xrootd to restore files from HPSS that are not on disk. Files are either specified on the command line or provided in a file. The file names do not include the Xrootd url prefix.

% xprep -s glast-rdr /glast/Data/Flight/Level1/LPA/prod/1.81/recon/r0284007150_v000_recon.root /glast/Data/Flight/.....

or

% xprep -s -f <listfile>  glast-rdr
with 
% cat <listfile>
/glast/Data/Flight/Level1/LPA/prod/1.81/recon/r0284007150_v000_recon.root
/glast/Data/Flight/Level1/LPA/prod/1.81/recon/r0284057424_v000_recon.root
.....

The xprep command will issue the request to the redirector and exit without waiting for the restore to finish. The redirector will look up the requested files and record there location (which Xrootd server has a file) in its lookup cache. For files that are not on disk the redirector will send a restore request to a data server that is allowed to restore files (-s option). There is no notification ones all files are on disk but a client has to check for them self.