On 11/05/2012 04:03 AM, Stefan Priebe - Profihost AG wrote:
Hello list, is the following syntax to use the new rbd v2 striping feature correct? rbd create -p kvmstor --format 2 --size 32000 --stripe-count 8 --stripe-unit 131072 -s 1048576 $imagename Idea is to have 8 stripes per 1MB object size. Or are there any other recommondations regarding striping?
The stripe count is actually how many objects to stripe over before repeating back to the first one. It's the number of objects in an 'object set' in the diagram at the bottom of: http://ceph.com/docs/master/dev/file-striping/ I don't think we've done enough benchmarks to know what the best settings are, but generally having large (like 4MB) objects and smaller stripe units will at least help small sequential I/O.
I'm a bit confused cause rbd info shows stripe-count as bytes?
It's not actually bytes. Sage just fixed that output in the master branch. Josh -- 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
