Hi Pavel,

We strongly discourage using a data server for a redirector at the first
point of contact. The reason is that the load becomes so unpredictable
that clients may start timing out when contacting the redirector. This is
a general problem of trying to run two distinctly different services on
the same machine (e.g., batch worker and nfs server). That said, yes you
can use the same machine to do both jobs but you will need to:

a) Configure a standard redirector (i.e., xrootd in reditect remote mode
and olbd in manager mode).

b) Start another xrootd (choose any port you want -- is doesn't matter) in
redirect target mode and configure it to connect to another olbd that you
start on the same machine in server mode. That olbd will subscribe to the
other olbd runnng on the same machine.

Clients needing to use the machine for data will be redirected to the
other xrootd on the same machine. However, they will be told use use the
alternate port.

I've tried only once during SC2004 and it appeared to work.


On Mon, 21 Feb 2005, Pavel Jakl wrote:

> Hello,
> I want to deploy XROOTD here in RCF RHIC and I would like to ask for one
> question.
> 1) Can redirector server be a data server ?  (i.e if data can be stored
> in redirector server and clients can access them)
>     I started redirector server (xrd and olb) on node
> with configuration file (in
> attachment) and data server on
>     Then I tried to open file which is located on node rcas6001.
>     root.exe [1]
> gROOT->GetPluginManager()->AddHandler("TFile","^root:","XTNetFile",
> "XTNetFile", "XTNetFile(const char*,Option_t*,const char*,Int_t,Int_t)");
>     root.exe [2] f =
> TFile::Open("root://")
>     Error in <TXNetConn::Open>: Server [] did
> not return OK message for last request.
>     Error in <TXNetConn::SendGenCommand>: Server declared error 3005:
> 'No servers are available to read the file.'
>     Error in <XTNetFile::CTOR>: Error opening the file
> //data1/starlib/reco/production62GeV/ReversedFullField/P04ie/2004/087/st_physics_adc_5087079_raw_2070001.MuDst.root
> on host
> I also inclose config files and log files , but I think that there is a
> simple question if it is possible or not. If yes, please can you give me
> a advice ?
> Thank you
> Pavel Jakl