We are currently installing Postgresql from the PostgreSQL apt repository. Is there some way to get "apt-get install postgresql-9.6" to use the --data-checksums option when setting up the cluster?
Or do we need to install Postgresql differently?
When you use apt-get, it creates a cluster without data checksum. All you have to do is to drop the newly created cluster:
pg_dropcluster 9.6 main
and create a new one with that option
pg_createcluster 9.6 <clusterName> <Youroptions (datachecksum for example)>
Or you can change the file
/usr/share/postgresql-common/createcluster.conf to put your data-checksum option there.