On 04/28/2015 06:25 PM, Mark Nelson wrote:
Hi Guys, Sage has been furiously working away at fixing bugs in newstore and improving performance. Specifically we've been focused on write performance as newstore was lagging filestore but quite a bit previously. A lot of work has gone into implementing libaio behind the scenes and as a result performance on spinning disks with SSD WAL (and SSD backed rocksdb) has improved pretty dramatically. It's now often beating filestore: http://nhm.ceph.com/newstore/newstore-5d96fe6-no_overlay.pdf On the other hand, sequential writes are slower than random writes when the OSD, DB, and WAL are all on the same device be it a spinning disk or SSD. In this situation newstore does better with random writes and sometimes beats filestore (such as in the everything-on-spinning disk tests, and when IO sizes are small in the everything-on-ssd tests). Newstore is changing daily so keep in mind that these results are almost assuredly going to change. An interesting area of investigation will be why sequential writes are slower than random writes, and whether or not we are being limited by rocksdb ingest speed and how. I've also uploaded a quick perf call-graph I grabbed during the "all-SSD" 32KB sequential write test to see if rocksdb was starving one of the cores, but found something that looks quite a bit different: http://nhm.ceph.com/newstore/newstore-5d96fe6-no_overlay.pdf
Oops, wrong link: nhm.ceph.com/newstore/newstore_perf_report_32k_write_ssd.txt.gz
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