Hi, Pablo!

Yuor idea seems to look very similar to what we have done with
Jean-Yves at T1_IN2P3, where xrootd cluster uses dcache as mass
storage, and files are "staged in" to xrootd from dcache when root
clients open them, and garbage collected to free up space.(actually we
also have a real MSS, HPSS, in play, but this changes nothing).

I can send you the complete set of scripts we have, next week. Our
base setup is somewhat similar to slac setup, plus some extra dcache
glue scripts. With xrootd, a quick sucess is in cloning someone else's
setup exactly, otherwise you'll sweat a lot. :))


On Jan 31, 2008 8:00 PM, Pablo Fernandez
<[log in to unmask]> wrote:
> Hi,
> We're building a Tier3 facility in the same place as our Tier2, that runs
> dCache (with LCG software). The main idea is to use the olbd as a temporal,
> volatile storage, caching the permanent data stored in the Tier2 MSS.
> I'm new to this list, and wandering around the archives I couldn't find
> accurate information about this. I've read many documents about the theory,
> but not much about practice.
> I'm finding it really difficult to find good information to build such system
> myself. So far the way to do this is via oss.msscmd and oss.stagecmd, that
> require two different scripts/programs that perform the operation in the MSS.
> With the information in
> one should be able to
> build both, but there's not any example there or anywhere I've seen. Does
> anybody here own a working example of both scripts and the xrootd config
> file? It will save us a lot of time.
> Also, I've read there's a set of daemons that take care of deleting old data
> to make space for the new, touching files that are being used, and so on.
> Does it have any relation with xrootd, or anyone can lead me to more precise
> and technical information about it? (also, access to the daemons themselves
> would be nice)
> Thanks a lot,
> Pablo Fernandez