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Hi Patrick, Since you specified "xrd/cache*" there is no need for a conditional. However, I am confused about mounting here. You should mount each file system as /xrd/chacenn where nn is a "number" mount point. So each system would have a variable number of mount points predefined. That would be my take but it sounds like you planning on doing something else. Andy ----- Original Message ----- From: "Patrick McGuigan" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, November 08, 2007 2:56 AM Subject: Re: Question about oss.cache directive > 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 >>> >