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
http://xrootd.slac.stanford.edu/doc/dev/ofs_config.htm 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,