Re: RBD performance - tuning hints / major slowdown effect(s)

[Dieter Kasper <d.kasper@kabelmail.de>]

Mark, Inktank,

OK, it is very likely that 'sync_file_range' is not the major slowdown 'culprit'.

But, which areas (design, current implementation, protocol, interconnect, tuning parameter, ...)
would you rate as 'major slowdown effect(s)' ?

Best Regards,
-Dieter


On Fri, Aug 31, 2012 at 08:48:34PM +1200, Mark Kirkwood wrote:
> On 31/08/12 20:11, Dietmar Maurer wrote:
> >>>RBD waits for the data to be on disk on all replicas. It's pretty easy
> >>>to relax this to in memory on all replicas, but there's no option for
> >>>that right now.
> >I thought that is dangerous, because you can loose data?
> >N???????????????r??????y?????????b???X????????v???^???)??{.n???+?????????z???]z???{ay???\x1d???????,j\a??????f?????????h?????????z???\x1e???w?????????\f?????????j:+v?????????w???j???m????????????\a????????????zZ+????????j"??????!tml=
> 
> And it is not immediately obvious that this is the bottleneck - from
> what I can see the 'sync' call being used (sync_file_range) is
> extremely fast and is *not* the major slowdown effect...
> 
> Regards
> 
> Mark
>