In 2.79 I used to create several Render Layers in order to optimize rendering time. I sometimes use a sphere with an emission shader to simulate the sky. It doesn't require many samples to be rendered accurately. So having a sky rendered with a minimal number of samples and the rest with bigger samples numbers was quite efficient. And as compositing is powerful in blender; all was kind of easy.
In 2.80 I can group objects in collections make several "View Layers" and use "Holdout" to achieve the same thing for compositing. But I cannot find any individual View Layers setting for samples. I have one setting and it seems to be global.
In other words I'm looking for a "per View Layer Sample setting". What I would like to achieve is to render my "sky View Layer" at 8 samples (as an example) and the other View Layers at 640 samples.
I can't find anything on the matter to my despair.
The suggestion to use
>Scene>ViewLayerXXX>Override>Sample doesn't seems to work. I tried different values than the global one (=23 samples) for each ViewLayer and it end up rendering with the global setting. Both on Linux and Windows10 version (x64 portable packages)
This may suggest that
>Scene>Render>Sampling>Layer Samples=Use isn't related to ViewLayer, though it could be appropriate considering the 2.79 -> 2.80 context.