Re: newstore performance update

[Mark Nelson <mnelson@redhat.com>]

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

>
> Mark
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