Postgresql - No PostgreSQL clusters exist; see "man pg_createcluster" during service restart
After the shutdown of the server PG was unable to start, the cluster (the instance of the database) was missing.
At the end I've been able to recover it. I had to correct something (see below) then I've executed :
sudo pg_createcluster 9.3 main
Then you should start it
sudo /etc/init.d/postgresql start
The system replied with : Configuring already existing cluster ....
Things to do in those cases : - check that all the configuration files and data files are in the correct folders - check that the files postmaster.opts are pointing to the correct locations
If the primary cluster (usually 'main') is still not starting you can create a new cluster with :
pg_createcluster 9.3 cluster2
Then restore the database backup to the new cluster.
Commands to control PG clusters :
list clusters
pg_lsclusters
start/stop a cluster
pg_ctlcluster <pg version> <cluster name> <start|stop>
pg_ctlcluster 9.3 main start
pg_ctlcluster 9.3 clust2 stop
stop a cluster - drop active connections
pg_ctlcluster -m fast 9.3 clust2 stop