AFS Home Directory
By default you get a fairly small AFS quota on your home directory. You can ask unix-admin to increase it to 500MB or for other volumes to be added to your home directory with a quota of 500MB. SCCS has a formto make this request.
NFS filesystems
Dedicated ATLAS scratch space is available. You should create a directory for yourself with the format:/afs/slac.stanford.edu/g/atlas/work/<firstLetterOfUsername>/<username>. It is actually an NFS disk space not backed up so that code are recommended to remain on your AFS space. For the moment this space is not automatically cleaned up, if it fills up we'll need to start doing that. Currently there are two 125GB volumes making up this space.
This space should be used for log files and other small files that don't need high performance access.
xrootd user space
This space is primarily for storing ROOT files, any type (POOL, ntuples, whatever). xrootd offers high performance access to these types of files.
Access to this area is either directly from ROOT or by copying files in or out via xrdcp. The recommended access type is to use direct access for reading and to write via xrdcp (write the output to a local disk on the machine your job is on, this is /scratch on the batch workers with scratch space, or /usr/work on the interactive machines).
Files in xrootd have a URL-type format. You can add them to a job and Athena knows how to use them. An example file would be:
To access it in ROOT directly, do:
root[0] TXNetFile f("{{root://atl-xrdr//atlas/xrootd/usr/g/gowdy/myFile.root");
To copy files in and out of xrootd:}}
xrdcp myFile.root root://atl-xrdr//atlas/xrootd/usr/g/gowdy/
{{xrdcp root://atl-xrdr//atlas/xrootd/usr/g/gowdy/myFile.root .
}}
Filesystem type access is not transparent currently due to the distributed nature of the xrootd system. However, the xrootd filesystem is MOUNTED on atlint01. You can should make a directory called /"first letter"/"username"/ in /xrootd/atlas/usr.
{{ssh atlint01.slac.stanford.edu
df
xrootdfs 59055800320 36962839968 22092960352 63% /xrootd/atlas/usr
xrootdfs 59055800320 36962839968 22092960352 63% /xrootd/atlas/dq2
xrootdfs 59055800320 36962839968 22092960352 63% /xrootd/atlas/atlasdatadisk
xrootdfs 59055800320 36962839968 22092960352 63% /xrootd/atlas/atlasmcdisk
xrootdfs 59055800320 36962839968 22092960352 63% /xrootd/atlas/atlasuserdisk
xrootdfs 59055800320 36962839968 22092960352 63% /xrootd/atlas/atlasgroupdisk
cat /xrootd/atlas/usr/a/ahaas/test.txt}}