Backing up Kallithea
Settings
Just copy your .ini file, it contains all Kallithea settings.
Whoosh index
The Whoosh index is located in the data/index directory where you installed Kallithea, i.e., the same place where the ini file is located
Database
When using sqlite just copy kallithea.db. Any other database engine requires a manual backup operation.
A database backup will contain all gathered statistics.