On Wed, Oct 27, 2010 at 12:33:35AM +0200, Michael Monnerie wrote: > Does anybody have a report how XFS behaves on a NetApp storage with thin > provisioning? They have a completely "weird" storage, their WAFL (write > anywhere file layout) together with deduplication and other things make > me think the best is to not-at-all specify any "performance options" in > mkfs/mount, like sunit/swidth or largeio, swalloc, etc. > > Does someone have information on that? Not about the Netapp as such. However, as a general rule thin provisioned storage will have unpredictable performance characteristics as the block number/physical location correlation is meaningless. e.g. because the log is one of the first things written to a thinly provisioned volume during mkfs, it is unlikely to be physically located in the middle of the volume. Indeed, there's no guarantee that it will even be on the same spindles as the rest of the filesystem, and it may be sharing spindles with some other thin volume.... So, you are right in assuming that it is best not to tune your filesystem to a specific physical geometry because there generally isn't one for thinly provisioned volumes. However, options that reduce filesystem fragmentation (e.g. allocsize) still have value in keeping the amount of metadata and ptotential seeks down... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
