Hi Andy,
On Wed, Sep 01, 2004 at 07:37:20AM -0700, Andrew Hanushevsky wrote:
> >
> > xcp "root://host:port//some/path/*" .
> >
> > I assume you don't want to support this due to the dynamic nature of
> > the catalog when using the redirector. (FWIW, I agree with that.) But
> > does it make sense if done on a dataserver?
> Only under some interpretations. If you're trying to copy what is there,
> then it makes sense. If you're trying to copy what should be there, then
> it doesn't make sense. In any case, it requires that the client do a
> directory listing and generate individual copies.
In this case "client" = xcp (or xrdcp, you ducked the naming question), is
that correct?
The two complications here are:
o replicas on multiple servers
o tertiary storage (including both mass storage and eventually "the world"
via the proxies)
I don't know how others feel, but I'm happy with a solution (in xcp/xrdcp)
that skirts the issue and does the following:
(a) Simply stops with an error message if one tries to do such a wildcarded
copy via a load balancer instead of an actual dataserver. Can the
client application determine this?
(b) Gives me what is actually there on disk instead of what might be
out there in tertiary storage someplace.
So what subtleties am I missing? (If I get a file being copied in at that
moment I presumably get what is there at that point, just like with 'cp'.)
> > How is the directory treated in a load balanced/cache filesystem environment
> > for something like the following?
>
> > xcp aaa.root root://host:port//some/path/bbb.root
> >
> > Is "/some/path" just created automatically?
> >
> > Are there other important subtleties to this, in particular with the load
> > balancer?
> The 'some path' is not created authomatically. Additionally, doing a
> dirlist via the load balancer will invariable give you unwanted results
> because the xrootd on that machine simply returns what is in the directory
> on that machine. That's logical in the sense that any other machine is
> just as bad, potentially.
Since I may be going via the load-balancer to write the file, how do I
create the "/some/path"? I have no idea in advance to which server I will be
redirected. ("I" in this case being xcp/xrdcp.)
Pete
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