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Hi Gregory, a) Yes, Pete is right. Only one localroot directive is allowed. The last one specified takes effect. b) If you are using a release prior to 03/01 then exporting multiple file systems via the export directive does not work. Andy ----- Original Message ----- From: "Peter Elmer" <[log in to unmask]> To: "Gregory Schott" <[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 8:37 AM Subject: Re: How do we export multiple directories from xrootd.cf > Hi Gregory, > > On Thu, Mar 24, 2005 at 05:22:15PM +0100, Gregory Schott wrote: >> I am trying to export 3 different disks. I am using xrootd version >> 20050110-1339. I tried: >> >> xrootd.export /export/babar13/kanga/EventStore/store >> xrootd.export /export/babar14/kanga/EventStore/store >> xrootd.export /export/babar15/kanga/EventStore/store > > Note that this allows clients to access things externally as: > > root://host:port///export/babar13/kanga/EventStore/store/blaXXX > root://host:port///export/babar14/kanga/EventStore/store/blaYYY > root://host:port///export/babar15/kanga/EventStore/store/blaZZZ > etc. > > so it really isn't what you want. (You basically are letting some of the > details of the filesystems be visible externally.) > >> oss.localroot /export/babar13/kanga/EventStore/ >> oss.localroot /export/babar14/kanga/EventStore/ >> oss.localroot /export/babar15/kanga/EventStore/ >> xrootd.export /prod >> xrootd.export /store >> >> but neither worked (in the second case it works for babar15 only). Could >> you send me an example of your working setup? > > Using the "oss.localroot" directive is the right thing, since that allows > you hide the details of the local filesystem, so that clients can access > things as: > > root://host:port//store/blaXXX > root://host:port//store/blaYYY > root://host:port//store/blaZZZ > etc. > > The problem you have here is that each xrootd wants to see a _single_ > filesystem (with root=localroot) to export. By putting in three > "localroot" > directives, I assume that only the last one is kept as valid. > > 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.) > > b) Run one xrootd per gpfs filesystem (since they are o(8TB) each, this > probably isn't a disaster. > > 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....) > > Does that help? > > Pete > > >> On Sun, 27 Feb 2005, Andrew Hanushevsky wrote: >> >> > Hi Matt, >> > >> > Stephen is right. THe performance will not be very good. While you have >> > eased the load on nfs in terms of number of clients the overall speed >> > will >> > be limited to below nfs speeds. In general, nfs is a very poor >> > performer. >> > >> > Andy >> > >> > On Sun, 27 Feb 2005, Stephen J. Gowdy wrote: >> > >> >> Hi Matt, >> >> BTW, do you really want to serve an NFS disk via xrootd? I'm not >> >> sure what the benefits would be, perhaps teher server would cache the >> >> file >> >> to make it a little better than normal NFS if a lot of people open the >> >> same file... >> >> >> >> regards, >> >> >> >> Stephen. >> >> >> >> On Sun, 27 Feb 2005, Langston, Matthew David wrote: >> >> >> >>> We would like to export multiple directories from our xrootd server. >> >>> The version of xrootd we are running currently only supports >> >>> exporting one directory. This is our current xrootd.cf file: >> >>> >> >>> glast@glast01 $ cat xrootd.cf >> >>> xrootd.fslib libXrdOfs.so >> >>> oss.readonly >> >>> xrootd.export /nfs/farm/g/glast/ >> >>> >> >>> We would like to do something like this: >> >>> >> >>> glast@glast01 $ cat xrootd.cf >> >>> xrootd.fslib libXrdOfs.so >> >>> oss.readonly >> >>> xrootd.export /nfs/farm/g/glast/dir1 >> >>> xrootd.export /nfs/farm/g/glast/dir2 >> >>> >> >>> However, it appears that xrootd only takes the last "xrootd.export" >> >>> stanza. Is there a way to get multiple exports (maybe in a later >> >>> version of xrootd)? >> >>> >> >>> Warmest regards, Matt >> >>> > > > ------------------------------------------------------------------------- > Peter Elmer E-mail: [log in to unmask] Phone: +41 (22) 767-4644 > Address: CERN Division PPE, Bat. 32 2C-14, CH-1211 Geneva 23, Switzerland > ------------------------------------------------------------------------- >