 |
 |
Hi, just a quick answer, even if Andy can be more specific about that... Patrick McGuigan wrote: > Hi, > > I am setting up an xrootd cluster for the first time and I have a > question about the oss.cache directive. > > Some of my data servers have two partitions (and some have one) that I > want to use for storage. Is it true that the oss.cache directive MUST > be used to put two partitions into service? Yes, that is the way xrootd can be used as a partition aggregator, and show all the disk space in the same namespace. > How is load balancing > (based on space) managed on caches versus partitions? Are there any > performance penalties to using the cache directive? No performance penalties I am aware of. The server does its best to keep the partition balanced when it has to choose where to write. > > Finally, when a directory is created within a cache, does the directory > get created on both partitions? No, the partitions are used more or less as 'opaque store'. > > If the partition on a one mount server is /xrd1 and the partitions on > dual-mount server are /xrd1 and /xrd2, would the following snippet from > the config file be appropriate: > > > # > # > olb.path rw /xrd > # > oss.cache public /xrd* > # > xrootd.fslib /opt/xrootd/lib/libXrdOfs.so > xrootd.export /xrd > > looks ok in principle. Other people may provide working config files to you, just to copy stuff that's already been tested. BTW, Wilko, do you have a simple one? Fabrizio > > I am expecting this to create a global namespace rooted at /xrd that is > writable and would use both partitions of dual-mount data server. > > > > Thanks for any information, > > Patrick