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
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