Am 19.03.14 23:40, schrieb Shrinand Javadekar: > 1. Changing the partition power of the object server rings. I was > running with a partition power of 8. I ran some experiments changing > this to 4 and then even 0. Turned out that this actually hurt > performance. I confirmed that the number of directories created in the > objects directory was 2 ^ partition power. I guess with reduced number > of directories (in the case of 0, there was just one directory) there > was more contention at the xfs file-system causing the system to give > lower throughput. > > I tested with partition powers of 0, 4, 7, 8, 16. 7 because the swift > ring calculator suggested so [1]. I got the best throughput at 8 > rings.
You might also have a look at https://swiftstack.com/blog/2012/05/14/part-power-performance/ and https://answers.launchpad.net/swift/+question/211929 Be careful when selecting a low partition power - you can't change it later on and if you expect a significant growth of your cluster you might run into some trouble. Increasing the partition power later on requires a new ring, and that in turn requires copying a lot of data (either to a new cluster [1] or internally to other storage nodes [2]) and should only be done as a last resort Christian [1] https://github.com/stackforge/swiftsync [2] https://github.com/enovance/swift-ring-tool _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : [email protected] Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
