Storing Data on Castor

Castor is a storage manager system used to store physics production files and user files http://castor.web.cern.ch. It can be used to store large files that are too large for your lxplus account. The access to the files is however a bit different than on lxplus.

If your username on lxplus is myusername, then you will have a directory under: /castor/cern.ch/user/m/myusername. To make the access a little easier, it may be helpful to define a path $CASTOR to this directory (setenv CASTOR /castor/cern.ch/user/m/myusername in your .tcshrc file).

To access your data the normal unix-commands like ls, mkdir, etc. will not work. Instead you have to use special commands. The most important are:

• rfdir - List the files in the directory (used like ls).
• rfrename - Renames and/or moves a file to a different directory (used like mv).
• rfmkdir - Creates a new directory (used like mkdir).
• rfcp - Copies files (used like cp). Use the -r option to copy recursively.
• rfrm - Removes a file (used like rm).

A longer list of commands can be found here.

NOTE: Tab-completion does not work in castor!

If you want to write a miniDST, it may be a good idea to store it on castor, as the (mini)DST files usually tend to be large. To store them on castor, add a rfio: before the castor-path in your Python-options file:

DATAFILE='rfio:/castor/cern.ch/user/m/myusername/myfile.dst'

To access your files on castor in DaVinci, use the prefix castor: in your path for the datafile, e.g.

DATAFILE='PFN:castor:/castor/cern.ch/user/m/myusername/myfile.dst'