> 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:
> (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....)