On Tue, 2005-02-22 at 15:24 +0000, Steve Traylen wrote:
> On Tue, Feb 22, 2005 at 03:00:20PM +0000 or thereabouts, Owen Synge wrote:
> > On Tue, 2005-02-22 at 14:55 +0000, Alessandra Forti wrote:
> > > > Because data is transfered to and from these servers over the internet.
> > >
> > > So it skips head node and gridftp servers second layer (in the tier1
> > > architecture) as explained by Andrew few mails ago?
> >
> > The process is as follows,
> >
> > {A} Client contacts server and asks where to put the data
> > {B} Client Receive a "Transfer" URL which is where to place the data
> > {C} Client uploads the data to URL.
>
> Though in the case of SRM copy method is it?
>
> {A} Client contacts 1st SRM and asks it to transfer file to another 2nd SRM
> {B} 1st SRM asks 2nd SRM where to put the file.
> {C} 1st SRM tells backend dcache nodes to put the file where the 2nd SRM
> told it to put it.
>
> Steve
I think so, although other variations are possible.
push or pull mode essentially, in general it does not matter and both
should be supported if you listed to anyone but Peter K. who does not
think SRM third party copies are a good thing. (dependency graphs etc
but I suspect politics.) I don't think SRM 3rd Party copy is required
functionality, but I could easily be up to date.
Regards
Owen
>
>
> >
> > Regards
> >
> > Owen
> >
> >
> > > On Tue, 22 Feb 2005, Owen Synge wrote:
> > >
> > > > On Tue, 2005-02-22 at 14:41 +0000, Alessandra Forti wrote:
> > > >> So if there is no difference why using srmcp you need the data servers
> > > >> exposed to the internet?
> > > >
> > > >
> > > >> Are they SRMs themselves?
> > > >
> > > > No they are part of the SRM system but SRM its self is a redirecting API
> > > > which returns URL's to the data server.
> > > >
> > > >> Pehaps I haven't
> > > >> understood what an SRM is. I thought dcache was one of the SRMs, is it
> > > >> not?
> > > >
> > > > Dcache provides an SRM API and data servers to support SRM use so I
> > > > should say it is.
> > > >
> > > > Owen
> > > >
> > > >>
> > > >> cheers
> > > >> alessandra
> > > >>
> > > >> On Tue, 22 Feb 2005, Steve Traylen wrote:
> > > >>
> > > >>> On Tue, Feb 22, 2005 at 02:14:56PM +0000 or thereabouts, Owen Synge wrote:
> > > >>>> On Tue, 2005-02-22 at 14:05 +0000, Alessandra Forti wrote:
> > > >>>>> Hi Steve,
> > > >>>>>
> > > >>>>> as usual we are not talking the same language :) and I need a bit of
> > > >>>>> explanation.
> > > >>>>>
> > > >>>>>> I think everything is correct. Only addition is that the difference between
> > > >>>>>> CMS and the data challenge is that CMS do srmcp's where as the service
> > > >>>>>> challenge does a (get-turl && get-turl) , 3rd party g-u-c,
> > > >>>>>> (close-turl && close-turl). This is why the disk servers them selves
> > > >>>>>> must be exposed to internet in the CMS case since it is them that do the
> > > >>>>>> transfer for you and they do it non-passivly.
> > > >>>>>
> > > >>>>> what package does srmcp belong?
> > > >>>>
> > > >>>> d-cache-client-1.0-34
> > > >>>>
> > > >>>>> what package do get-turl/3rd party g-u-c/close-turl belong?
> > > >>>>
> > > >>>> Any Srm client. So probably the experimental code for CMS is my guess in
> > > >>>> this case.
> > > >>>>
> > > >>>>> what does g-u-c mean?
> > > >>>>
> > > >>>> I am guessing Steve means Globus URL Copy
> > > >>>>
> > > >>>>> what is the difference between the two?
> > > >>>>
> > > >>>> srmcp is written in Java, the rest are in C/C++.
> > > >>>>
> > > >>>> srmcp supports dcap.
> > > >>>>
> > > >>>> Apart from that, some WSDL passing, and some other trivial stuff not
> > > >>>> much from my knowledge, can you add more Steve?
> > > >>>
> > > >>> Not much, The srmcp supports the SRM cp method where you can ask one
> > > >>> SRM to copy a file to another SRM on your behalf thus making the
> > > >>> transfer asyrchonous.
> > > >>>
> > > >>> lcg-rep does a (get-source-turl,get-dest-turl), 3rd party globus-url-copy,
> > > >>> (close-source-turl,close-dest-turl) and is sychronous.
> > > >>>
> > > >>> Steve
> > > >>>
> > > >>>
> > > >>>
> > > >>>>
> > > >>>> Owen
> > > >>>
> > > >>> --
> > > >>> Steve Traylen
> > > >>> [log in to unmask]
> > > >>> http://www.gridpp.ac.uk/
> > > >>>
> > > >>
> > > >> --
> > > >> ********************************************
> > > >> * Dr Alessandra Forti *
> > > >> * Technical Coordinator - NorthGrid Tier2 *
> > > >> * http://www.hep.man.ac.uk/u/aforti *
> > > >> ********************************************
> > > >
> > >
> > > --
> > > ********************************************
> > > * Dr Alessandra Forti *
> > > * Technical Coordinator - NorthGrid Tier2 *
> > > * http://www.hep.man.ac.uk/u/aforti *
> > > ********************************************
>
> --
> Steve Traylen
> [log in to unmask]
> http://www.gridpp.ac.uk/
