Error: /var/lib/postgresql/9.3/main is not accessible or does not exist

Question

I have a PostgreSQL db that was running on my server. I tried to do a db_dump and got a weird error message. I eventually thought I would just restart PostgreSQL. However its now stopped and won't restart.

Error: /var/lib/postgresql/9.3/main is not accessible or does not exist

I get the error above when I try and run:

sudo service postgresql start

Can anyone give me some clue please?

I'm running on PostgreSQL 9.3 on Ubuntu 14.04

• András Váczi: And what was the weird error message? How did you take the dump? Is your installation in the directory in the title?

Answer 1

If you suspect there's something wrong with our database (cluster), make a copy of your database directory before you continue. Just to be sure. On Ubuntu the default directory would be: /var/lib/postgresql/9.3/main/ - but your installation may differ.

Actually, your command should work (in default Ubuntu installations), because the service command starts the postgres server process with appropriate privileges (as system user postgres)

sudo service postgresql start

Translates to something like:

sudo -u postgres /usr/lib/postgresql/9.3/bin/pg_ctl -D /var/lib/postgresql/9.3/main/ -o "-c config_file=/etc/postgresql/9.3/main/postgresql.conf" start

That starts all db clusters you may have. To start a particular one, use the wrapper pg_ctlcluster:

sudo -u postgres pg_ctlcluster 9.3 main start

To get the status of all currently installed db clusters use pg_lsclusters:

sudo -u postgres pg_lsclusters

You must be aware that the data directory is not the same as the config directory in default Debian or Ubuntu Postgres installations. For Postgres 9.3 that would be:

data dir: /var/lib/postgresql/9.3/main/
config dir: /etc/postgresql/9.3/main/

You can check the /etc/postgresql/9.3/main/postgrsql.conf for the actual data dir. It's the line starting with

data_directory = 

The error message indicates that Postgres tries to start with the default data dir, but it is not there or the privileges have been changed. Did you check?

Or are you running a non-default installation?

• Bernard: Thanks for the help. My installation (its a Digital Ocean server) is /etc/postgres/9.3/main However starting it as postgres didn't work. I got the same error message? Is there maybe some env setting that is out of whack?
• Erwin Brandstetter: @Bernard: I clarified a bit. I know nothing about Digital Ocean. Obviously a cloud service. If that means a modified Postgres installation all bets are off. Consult their help.
• Bernard: Thanks - DO is like Heroku. Its a standard postgres install as they don't have custom installs. They just give you a server and you choose the standard linux distros and install everything yourself. /var/lib/postgresql/9.3/main is my data directory according to postgresql.conf. However I have nothing in the /var/lib/postgresql/ folder except .ssh, .bash_history, .psql_history ? Its like its the postgres user's home folder or something as I tried to do a pg_dump as the postgres user and that backup is also in the folder - 0 bytes long though :(
• Bernard: root@myserver:~# pg_lsclusters Ver Cluster Port Status Owner Data directory Log file 9.3 main 5432 down <unknown> /var/lib/postgresql/9.3/main /var/log/postgresql/postgresql-9.3-main.log
• Bernard: Its totally weird - like my db has just disappeared?