> /var resides on /dev/sda, and /data in /dev/sdb
I bet you're running a default installation of postgres which has it's
data in /var.
Check your real data directory by running 'ps auxww|grep post', and see
what's after the '-D' parameter... and then when you figure out that the
startup script is using the system default and not what you've
initdb-ed, fix your start script ;-)
Cheers,
Csaba.