services.cassandra.heapNewSize

Must be left blank or set together with heapNewSize. If left blank a sensible value for the available amount of RAM and CPU cores is calculated.

Override to set the amount of memory to allocate to the JVM at start-up. For production use you may wish to adjust this for your environment. HEAP_NEWSIZE refers to the size of the young generation.

The main trade-off for the young generation is that the larger it is, the longer GC pause times will be. The shorter it is, the more expensive GC will be (usually).

The example HEAP_NEWSIZE assumes a modern 8-core+ machine for decent pause times. If in doubt, and if you do not particularly want to tweak, go with 100 MB per physical CPU core.