On Friday 15 July 2005 12:43, Burke, S (Stephen) wrote:
> Testbed Support for GridPP member institutes
> > [mailto:[log in to unmask]] On Behalf Of Graeme Stewart said:
> > Which it does by resolving an LFN to a SURL on a CLOSE_SE, right? My
> > point is really that CLOSE_SE is a very crude way to do this. In
> > practice Edinburgh is probably "close enough" to Glasgow
> There's nothing to stop Glasgow declaring Edinburgh as a close SE and
> vice versa.
This might actually be one of the few areas in which our T2s could behave as
anything other than "Just a Bunch Of Sites". For T2s with lowish amounts of
disk and suitable network connections sharing SEs would seem like a good
> It's true that it's an all-or-nothing thing at the moment;
> you could potentially have an extra attribute set by the admin to
> indicate the degree of closeness, but that would give more problems in
> configuration, how would the admin decide what number to use?
I think the only sensible way to move from the binary situation we have now
would be to have a dynamic scheme. It doesn't make sense for admins to have
to worry about this complexity when it can be monitored. Of course then the
RB has to have some algorithm for coming up with "close enough", or indeed
for it to be able to schedule a sensible file transfer and hold the job until
it's completed that.
> > I sense that it is believed that it's far to late to do
> > things properly now ;-)
> As I've said a few times over the years, I think there are three phases:
> 1) It's much too early to worry about something like that, we're just
> building a prototype. We'll sort out the details once we get the basic
> things working.
> 2) Yes, in principle that's a problem, but we have to release the code
> in three weeks so there's no time to do it now. We'll sort it out in the
> next release.
> 3) Yes, it's ugly, but the code is deployed on 200 sites and changes
> have to be backward-compatible so it's too late to change it now, we
> should have thought about it sooner ...
You clearly know far too much to be able to work in this field any more... ;-0
Dr Graeme Stewart http://www.astro.gla.ac.uk/users/graeme/
GridPP DM Wiki http://www.physics.gla.ac.uk/gridpp/datamanagement/