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Hi Gregory, Actually, you will be able to do this relatively easily in the next release since you will be able to run multiple xrootd servers on a single machine (actually you can do it now but it's a real pain to setup -- though Jean-Yves at IN2P3 does this somewhat regularly). Andy ----- Original Message ----- From: "Gregory Schott" <[log in to unmask]> To: "Peter Elmer" <[log in to unmask]> Cc: "Andrew Hanushevsky" <[log in to unmask]>; "Stephen J. Gowdy" <[log in to unmask]>; "Langston, Matthew David" <[log in to unmask]>; "xrootd-l" <[log in to unmask]> Sent: Thursday, March 24, 2005 9:26 AM Subject: Re: How do we export multiple directories from xrootd.cf > Hello Peter, > >> We just went through some of these things today at CNAF WRT gpfs (I >> recognize this is what you are using here). The solutions are: >> >> a) use the cache filesystem to tie the three gpfs filesystems together >> into one "namespace" to export (This is what is done at SLAC and most >> of the other sites that have more than one filesystem/server.) See: >> >> http://xrootd.slac.stanford.edu/doc/mps_config/mps_config.htm >> >> (I _really_ need to provide a simple example of this.) > > Yes, it would be nice to have an example. I'll try to use mps on Tuesday. > >> b) Run one xrootd per gpfs filesystem (since they are o(8TB) each, this >> probably isn't a disaster. > > Unfortunately I have only 2 GPFS fileservers and 3 disks so I cannot use > this as a solution without loosing a disk. > >> The fundamental issue here is that gpfs is trying to do one of the >> things >> that xrootd is trying to do, namely load balancing across the >> fileservers. >> They aren't incompatible, but the part that gpfs doesn't do (allow the >> separate filesystems to be treated as a single logical file space) has to >> be >> dealt with some way. The choices are really (a) or (b) above. (Or >> _really_ >> ugly solutions, like the current one being used by some of LHC >> experiments >> where the location of the file on a particular filesystem is being >> managed >> by an external catalog....) > > -- Gregory >