Does proof find out where date files are?

Dear rooters,
assume we have 4 workers, each with a local disk where data files
reside:
on worker 1: /data/aa/file1.root
on worker 2: /data/aa/file2.root
etc.
Note: Not each file is on each node, and files are not visible from
a different node.
Naively I thought proofs master + workers find out where the files
are and distribute the work accordingly.

Cheers
Otto [/quote]

Hi Otto,

What you described is exactly how PROOF works. However the files must be visible to the xrootd redirector node (which is also the PROOF master).
It can be achived with the xrootd.export directive in the xrootd config file as described on the PROOF wiki:
root.cern.ch/twiki/bin/view/ROOT/XpdExampletwo

in your case the directive would be:
xrootd.export /data/aa

In order to process the files you can create a TDSet or a TChain with the
urls of the files as if they were on the master. Urls will look similar to this:
root://master.domain//data/aa/file2.root

Cheers,
Jan