PostgreSQL server migration

migrate-psql-server.sh

$ locate bin/postgres
/usr/lib/postgresql/10/bin/postgres
/usr/lib/postgresql/12/bin/postgres
/usr/lib/postgresql/9.5/bin/postgres

$ sudo pg_lsclusters

$ mkdir backup-pg
$ sudo cp -R /var/lib/postgresql/9.5 backup-pg

$ sudo systemctl stop postgresql.service
$ sudo systemctl stop postgresql@12.service
$ sudo systemctl stop postgresql@9.5.service

$ cd /tmp
$ sudo -H -u postgres /usr/lib/postgresql/12/bin/pg_upgrade \
 -b /usr/lib/postgresql/9.5/bin \
 -B /usr/lib/postgresql/12/bin \
 -d /var/lib/postgresql/9.5/main \
 -D /var/lib/postgresql/12/main \
 -o ' -c config_file=/etc/postgresql/9.5/main/postgresql.conf' \
 -O ' -c config_file=/etc/postgresql/12/main/postgresql.conf'

$ sudo systemctl start postgresql.service
 
$ sudo ./analyze_new_cluster.sh

$ sudo ./delete_old_cluster.sh

$ # delete and clean old data....