Please, help! About database cluster and adding to it additional disk space

[Sergey Karin <sergey.karin@xxxxxxxxx>]

Hi, List!

Lets suppose the next situation...

We create database cluster (via initdb) on some disk. Then we create
and use a database that can be very large. In some moment the database
occupy all disk space allicated to cluster. 
The question is: are there any abilities in PostgreSQL to use for
created cluster additional disk space in new other disk? Similar
ability exist in Informix...

Thanks in advance for any answers!

Sergey Karin