The default value of maxMergedSegmentMB=5000 perfectly works for databases smaller or slightly larger than 5GB.
It is recommended to increase maxMergedSegmentMB when the database grows larger.
I wonder what is the rule of thumb for tuning this value for very large databases?
For example, if a database is 1TB, is it practical to have 1 segment of 1TB or 200 segments of default 5G? In practice, it should be something in between, but how do you decide about it?