[sheepdog-users] 答复: sheepdog data write performance with 5 node

[Liu Yuan]

On Mon, Nov 25, 2013 at 08:49:42AM +0100, Gerald Richter - ECOS wrote:
> > 
> > I have added an entry on this topic
> > 
> > https://github.com/sheepdog/sheepdog/wiki/Why-The-Performance-Of-
> > My-Cluster-Is-Bad
> > 
> 
> Thanks for adding this, it is very helpful. One question is left:
> 
> Which combination of cache/journal/nosync makes sense. For highest performance does it make sense to use all three, or might it better to just use cache+nosync, because journal causes extra disk writes (cache to overcome network latency and nosync to get better write performance on the server).
> 
> Which combinations of these three make sense?

I think 

1 object cache + nosync (like sheep -w size=200G -n, best when host memory is big enough)
  object cache + nosync (like sheep -w size=200G,directio -n)

2 object cache + journal (like sheep -w size=200G -j size=8G)

makes sense and you'll experience better performance with 1 than with 2. And
'nosync' | journal duplicate each other, so setting either one is good enough.

Thanks
Yuan