Disk full problem

Hi all,

I am a new addition to this mailing list. I am using Postgresql 7.4.3.
I went through the postgresql documentation for saving the disk usage.
Accordingly i changed the checkpoint_segments parameter to 1 in the
postgresql.conf file. I cross checked by giving the SHOW ALL command.
It shows 1 for the checkpoint_segments parameter. But when I chk the
disk usage, the pg_xlog folder is taking up 65MB. There are 4 files
under pg_xlog folder. According to the documentation, it should be
taking only 16MB.

And one more thing I noticed was that the base folder under pgsql/data
folder is taking up 25MB space.

How do I reduce the space taken up by these folders. I am running the
vaccumdb command at regular intervals.

Thanks in advance.