Writing to EOS¶

The Purdue EOS storage is mounted read-only at /eos/purdue/. To write files to EOS (for example, to your Grid directory /store/user/<cern-username>/), use the gfal or xrdcp/xrdfs commands.

A typical workflow is: save job outputs into /tmp/<username>/ (on the session, Slurm job, or Dask worker that produced them), then copy them to EOS — see Storage volumes for why this is preferred over writing to Depot from many jobs at once.

Using xrdcp and xrdfs¶

This option only requires a valid VOMS proxy. For example:

# copy a local file to your Grid directory on Purdue EOS
xrdcp /tmp/$USER/output.root root://eos.cms.rcac.purdue.edu//store/user/<cern-username>/output.root

# list the contents of a directory
xrdfs root://eos.cms.rcac.purdue.edu ls /store/user/<cern-username>/

Documentation on xrdcp is available at the Purdue Tier-2 CMS site.

Using gfal¶

The gfal commands are documented at the Purdue Tier-2 CMS site. They are available in every terminal and also require a valid VOMS proxy. For example:

gfal-copy /tmp/$USER/output.root root://eos.cms.rcac.purdue.edu//store/user/<cern-username>/output.root