in OCaml, copying GC is used only in the young generation. functional languages allocate lots of shortly lived objects, so copying gc is a good fit, since allocation is the cheapest possible, and as only a few objecta survive a gc, the cost of copying them is low. Since the GC is generational, objecta get copied at most n times, for some n.
the JVM (HotSpot) also uses this approach, the young generation is handled by a copying GC while the older one(s) use mark & sweep.
(to be fair, I believe this _was_ the default GC option, but it's not anymore, and there were at least 3 different young generation GC algorithms that used copying, so it's a bit more nuanced)
