OK, I found this nice page: http://ceph.com/docs/next/dev/file-striping/ which explains "--stripe_unit --stripe_count --object_size" But still I'm not sure about (1) what is the equivalent command on cephfs to 'rbd create --order 16' ? (2) how to use those parameters to achieve different optimized layouts on CephFS directories (e.g. for streaming, small sequential IOs, small random IOs) -Dieter On Fri, Aug 09, 2013 at 09:44:57AM +0200, Kasper Dieter wrote: > Hi, > > my goal is to set the 'object size' used in the distribution inside rados > in an equal (or similar) way between RBD and CephFS. > > To set obj_size=64k in RBD I use the command: > rbd create --size 1024000 --pool SSD-r2 ssd2-1T-64k --order 16 > > On cephfs set_layout '-s 65536' runs into EINVAL: > cephfs /mnt/cephfs/fio-64k/ set_layout -p 3 -s 65536 -u 4194304 -c 1 > Error setting layout: Invalid argument > > cephfs /mnt/cephfs/fio-64k/ set_layout -p 3 -s 65536 -u 65536 -c 1 > cephfs /mnt/cephfs/fio-64k/ show_layout > layout.data_pool: 3 > layout.object_size: 65536 > layout.stripe_unit: 65536 > layout.stripe_count: 1 > > The man page of cephfs says > ---snip--- > -u --stripe_unit > Set the size of each stripe > > -c --stripe_count > Set the number of objects to stripe across > > -s --object_size > Set the size of the objects to stripe across > ---snip--- > > What is the equivalent command on cephfs to 'rbd create --order 16' ? > Can you please give same explanation how "--stripe_unit --stripe_count --object_size" > should be used in combination to achieve different layouts on CephFS directories > (e.g. optimized for streaming, small sequential IOs, small random IOs) > ? > > Thanks, > -Dieter -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
