You can render raster on the fly from a vector based tileserver, and optionally use vector maps for clients where it makes sense (mobile for example).
I've been running a large OSM raster rendering stack for a while, for the whole planet. Moving on to a vector based stack right now, which is what you should do if you are starting today. The reason being the server, with vector tiles pre-rendered, can very quickly render raster tiles on the fly. It's fast enough that for most cases, there is no need to cache them. Once I get the new stack fully burned in, we'll swap our raster rendering stack out for the new vector stuff and do raster on the fly. I might cache the rasters depending on throughput, but from what I can tell it should be basically a non-issue.
I've been running a large OSM raster rendering stack for a while, for the whole planet. Moving on to a vector based stack right now, which is what you should do if you are starting today. The reason being the server, with vector tiles pre-rendered, can very quickly render raster tiles on the fly. It's fast enough that for most cases, there is no need to cache them. Once I get the new stack fully burned in, we'll swap our raster rendering stack out for the new vector stuff and do raster on the fly. I might cache the rasters depending on throughput, but from what I can tell it should be basically a non-issue.