I've worked in applications where a lot of IO is required. If performance is something your application cares about then you'll probably end up using direct ByteBuffers which are off heap and you'll likely want to set a sensible value for: -XX:MaxDirectMemorySize

However if this value ever does get exceeded, you need some way of tracking down what allocations happened prior to your OutOfMemory exception.

Though the above article implies the sampling rate is once a second (I guess there's some cost to increasing that rate). Usually you won't be allocating direct memory on the reg since it's expensive to allocate and deallocate relative to heap memory so you kind of want to capture ALL allocations and deallocations. As such a sample based approach is not ideal due to possibly missing some data between samples.