Using Xcache at SLAC¶
Xcache enables to access data remotely and also to cache them locally for faster access in future.
The Xcache server at SLAC is root://atlfax.slac.stanford.edu/,
We will try to cache the files located at BNL. Let us take the input file used in the BNL example. At BNL, the inputFile name is
inputFile=root://dcgftp.usatlas.bnl.gov:1096/pnfs/usatlas.bnl.gov/LOCALGROUPDISK/rucio/data18_13TeV/da/ea/DAOD_EXOT12.14278917._000001.pool.root.1
The port 1096 is for inside access. For outside access, the port is 1094. So, the inputFile becomes
inputFile=root://dcgftp.usatlas.bnl.gov:1094/pnfs/usatlas.bnl.gov/LOCALGROUPDISK/rucio/data18_13TeV/da/ea/DAOD_EXOT12.14278917._000001.pool.root.1
For Xcache, we need add the Xcache server prefix with two slash characters, that is,
inputFile=root://atlfax.slac.stanford.edu//root://dcgftp.usatlas.bnl.gov:1094/pnfs/usatlas.bnl.gov/LOCALGROUPDISK/rucio/data18_13TeV/da/ea/DAOD_EXOT12.14278917._000001.pool.root.1
cd Interactive-Job
../bin/Exam_JetsPlot $inputFile > myjob.log 2>&1
With gLFN¶
Xcache at SLAC also supports gLFN (global Logical File Name) access, without knowing the exact path of a given filename.
Let us take the same dataset used in the BNL example.
$ rucio list-dataset-replicas $dset
DATASET: data18_13TeV:data18_13TeV.00348885.physics_Main.deriv.DAOD_EXOT12.f937_m1972_p3553_tid14278917_00
+-------------------------+---------+---------+
| RSE | FOUND | TOTAL |
|-------------------------+---------+---------|
| CERN-PROD_DATADISK | 83 | 83 |
| GRIF-LPNHE_DATADISK | 83 | 83 |
| BNL-OSG2_LOCALGROUPDISK | 83 | 83 |
| MAINZ_LOCALGROUPDISK | 83 | 83 |
+-------------------------+---------+---------+
List just the filenames in the dataset
$ rucio list-content $dset
+-------------------------------------------------------+--------------+
| SCOPE:NAME | [DID TYPE] |
|-------------------------------------------------------+--------------|
| data18_13TeV:DAOD_EXOT12.14278917._000001.pool.root.1 | FILE |
| data18_13TeV:DAOD_EXOT12.14278917._000002.pool.root.1 | FILE |
...
Let us take the second one file.