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).
----- 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:
>> (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
>> that xrootd is trying to do, namely load balancing across the
>> 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
>> dealt with some way. The choices are really (a) or (b) above. (Or
>> ugly solutions, like the current one being used by some of LHC
>> where the location of the file on a particular filesystem is being
>> by an external catalog....)
> -- Gregory