Copying database to different hard disk Total noob at database administration here, excuse my ignorance.

I have a server running a Rails application that's using PostgreSQL. The database is saved on drive /z/, which seems to have filled up. I want to put a higher capacity drive and shift the database to that. How should I go about doing this? Should I copy the data folder from drive /z/ to the new drive and then change the config files (could someone point me to what config changes I need to make?)

Or could I copy the data folder to the new hard disk, and then mount the disk as /z/ and then I'll need no config changes? 

Or is there some helper commands in postgres that provide a functionality to migrate between disks?

I'm running Ubuntu 12.04.5 LTS. Output of version():  


  PostgreSQL 9.3.5 on x86_64-unknown-linux-gnu, compiled by gcc
  (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3, 64-bit
if you add a second disk i suggest to put data on to different tablespaces. a tablespace offers additional storage and is VERY easy to use:

mkdir /whatever


then in SQL:

CREATE TABLESPACE myspace LOCATION '/whatever';
ALTER DATABASE x SET TABLESPACE myspace;


of course you can also do this for single tables only.
and yes, alternatively you can move the entire data dir and tell the system where the new location is.