> > Is the cutoff for the deferred writes > 64kb or >= 64kb by default? > I.e., is a 64kb write deferred or not by default? > Looks like its <= https://github.com/ceph/ceph/blob/864594f473da1f04c476eb27073a8c2ea735a982/src/os/bluestore/BlueStore.cc#L10487 And checking the default options, it looks like it's now 32kb, not 64kb from what I remember, so apologies for that. > > Paul > Am Do., 11. Okt. 2018 um 00:37 Uhr schrieb Sage Weil <sage@xxxxxxxxxxxx>: > > > > On Wed, 10 Oct 2018, Nick Fisk wrote: > > > Following up from a discussion on the performance call last week. > > > > > > Is anybody able to confirm the behaviour of Bluestore deferred writes with new objects? > > > > > > From my testing it appears that new object are always directly > > > written to the underlying block device and not buffered into flash, whereas existing objects <64KB are. > > > > I just did a quick test (on master) and it looks like the deferred > > writes are working as expected in that they *do* apply to new objects > > (as well as existing ones). Can you be a bit more specific about what > > you observed? (which version? what workload?) > > > > Thanks! > > sage > > > > > -- > Paul Emmerich > > Looking for help with your Ceph cluster? Contact us at https://croit.io > > croit GmbH > Freseniusstr. 31h > 81247 München > www.croit.io > Tel: +49 89 1896585 90
