Resizing hard disk partition without losing data

[cool11]

I would never opened a topic like this if I had not a similar experience with expanding 'dmg' in the past!
A truly bad experience! It is supposed that using 'disk utility' I can resize-expand-make bigger any dmg file. Every time I tried it, it was a totally fail process.
The 'disk image' dmg did not resized at all.
I do not know why, it just happened to me many times. Does anyone had similar experience? Any solution to this?
So if I have a dmg that need to be bigger, I create a new one from scratch and I copy paste files from the old dmg...

I need to do the same with hard disk partitions, using disk utility once again. I need to resize my hard disk partitions.
Does this process works well as it should be, or it is a bad-implemented feature?
Will it be a trouble-free procedure or it is common to mac users to face problems with it?
I had the similar bad experience with dmg's, so I am suspicious now.

 

[JNB]

Disk images and drive partitions are completely separate things, and resizing is handled differently. Resizing a dmg requires that it be unmounted, then you are able to select the Resize Image icon. From the dialog that follows, you choose the dmg to be resized. I just did it, and it works perfectly.

Mounted partitions can be resized non-destructively in Disk Utility.

 

[MacManiac76]

Mounted partitions can be resized non-destructively in Disk Utility.

Just a little FYI I discovered by accident is that Journaling must be enabled to be able to resize partitions non-destructively in Disk Utility. I turned off Journaling for some reason and then tried to resize my partitions, but it wouldn't let me do it non-destructively until I turned Journaling back on.