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Hi, A follow question concerning how the config file would be handled by systems with one mount. Consider: oss.cache public /xrd/cache* xrootd.fslib /opt/xrootd/lib/libXrdOfs.so xrootd.export /xrd On systems with multiple partitions, I would mount: /xrd /xrd/cache00 ... /xrd/cacheNN On systems with one partition, I would mount /xrd Will this work, or does the oss.cache directive need to wrapped in a conditional statement so that it is only used on multi-partition servers? Patrick Wilko Kroeger wrote: > > Hello Patrick > > Fabrizio answered already most of the question. I just have a few comments. > > If you have more then one partition that an xrootd server should serve > you should use the cache directive. > The cache is working by placing a file in a cache directory and creating > a link between this file and the proper file name. For example: > if the file name is /xrd/test/d1/file1 and your you use the the cache > directive > ooss.cache /xrd* > the file would be put (lets pick cache xrd2) into > /xrd2/%xrd%test%d1%file1 > and a link is created: >> ls -l /xrd/test/d1/file1 -> /xrd2/%xrd%test%d1%file1 > > As you can see there are no directories in the cache. The file name in > the cache is the proper file name with all '/' replaced by '%'. > > > As xrootd will export /xrd you have to create a /xrd directory. I guess > this will not be in the '/' root partition but in one of you data > partition (/xrd1 /xrd2) and therefore you will need a link. > /xrd -> /xrd1 > > However, in this case, doing an 'ls /xrd' would list all files in /xrd1 > which could be quite large depending how many files you have. Therefore, > you might want to have a link like > /xrd -> /xrd1/xrd > In this case 'ls /xrd' would not list the files in the /xrd1 cache. > > Another possibility would be to make the cache directories a little bit > more explicit. Mount your two partitions as: > /xrd > /xrd/cache1 > and create the directory > /xrd/cache0 > and then use > ooss.cache /xrd/cache* > > I hope these comments helped a little bit. > > Cheers, > Wilko > > > > On Wed, 7 Nov 2007, 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? How is load balancing >> (based on space) managed on caches versus partitions? Are there any >> performance penalties to using the cache directive? >> >> Finally, when a directory is created within a cache, does the >> directory get created on both partitions? >> >> >> >> 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 >> >> >> >> 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 >>