The (uncompressed) changelog and actionlog size is currently 10MB and 2MB respectively.
On busy clusters (many concurrent chunk migrations and splits), I have seen the changelog window shrink to ~2 hours.
For diagnostic purposes it would be useful to increase the changelog and actionlog size to hold a longer time window.
- changelog: 200 MB (20x)
- actionlog: 20 MB (10x, as it tends to be less subject to writes in a busy cluster)