this is clearly a misbehaviour of the xrootd door of dCache.
Several problems with the current implementation of dCache's xrootd
server engine came up recently, which make us dCache people think about
rewriting the engine (mostly from scratch).
The most important goal of the new engine will being as compatible as
possible with XrdClient (thanks Farbrizio for the help you offered, it
is and will be very useful to improve compatibility). The engine will be
written in JAVA and be mostly decoupled from dCache. It will run
embeddeded in dCache doors as well as dCache pools, communicating with
the dCache backend via callbacks.
About PROOF: since some ATLAS guys (Munich and Brookhaven) trying to
integrate dCache with PROOF, this topic appeared on my radar and I will
certainly look into this.
Pablo Fernandez wrote:
> I've seen different behaviors in dCache xrootd door and the normal xrootd
> daemon, and before rising a ticket in dCache I wanted to ask you about what
> is normal and what's not.
> I've used an example of proof job that tries to access a set of files. First
> the files were stored in dCache (and accessible via xrdcrp commands), and I
> found errors accessing the file with the proof job. Afterwards I changed the
> location of the files to the olbd storage instead, and that didn't return
> errors accessing the files, it worked fine.
> The error returned by root for every file is:
> Srv err: Stat request requires open file.
> 01:42:23 3789 Mst-0 | Error in <TDSetElement::Lookup>: couldn't lookup
> (as you may have guessed, grid017 is the dCache xrootd door, and I'm sure it
> works because it can copy back that same file with xrdcp)
> And the error returned by the dCache xrootd door is (again for each file):
> LogicalStream(localPort=1094 SID=256) got new request from dispatcher
> Xrootd-Error-Response: ErrorNr=3004 ErrorMsg=Stat request requires open file.
> Xrootd-Response-Thread: sending response
> So, the error means that a "stat" operation was sent before opening the file.
> If the same access attempt succedes on a normal xrootd daemon and fails on
> dCache, what do you think? Is is xrootd daemon too permissive or dCache too
- IT -
Deutsches Elektronen-Synchrotron DESY
Fon: +49 40 8998 3639
Fax: +49 40 8994 3639