How to Enlarge a Volume Using Disk Utility
You can enlarge a volume as long as it’s not the last volume on the drive. You must be willing to delete the volume that is directly in back of the one you want to enlarge, along with its data. Make sure you have a current backup of all data on the drive you plan to modify. Here’s how to enlarge a volume.
Resizing Without Losing Data in Any Volume
It would be nice if you could resize volumes without having to delete a volume and lose any information you have stored there. With the new Disk Utility, that isn’t directly possible, but under the right circumstances, you can resize without losing data, although in a somewhat complicated manner. For example, you have two volumes on your selected drive, Stuff and More Stuff. Stuff and More Stuff each take up 50% of the drive space, but the data on More Stuff is only using a small part of its volume’s space. You can enlarge Stuff by reducing the size of More Stuff and then adding the now free space to Stuff. Here is how to do that:
Moving Data Using Disk Utility
Now we’ll add the newly freed-up space to “Stuff.”
Finishing the Resizing
Now, we’ll complete the volume resizing process.
The Rules of Resizing
Understanding how resizing works in Disk Utility will go a long way toward helping you resize a volume without experiencing any loss of information.
When enlarging a volume, the volume or partition that is directly after the target volume must be deleted to make room for the enlarged target volume. The last volume on a drive can’t be enlarged. The pie chart interface for adjusting volume size is picky. When possible, use the optional Size field to control the size of a drive segment instead of the pie chart’s dividers. Only drives formatted using the GUID Partition Map can be resized without losing data. Always back up your drive’s data before resizing a volume.
Resizing Wrap-Up
As you can see, resizing with the new version of Disk Utility can be simple, as shown in the first example, or convoluted as in the second example. In the second example, you could also use a third-party cloning app, such as Carbon Copy Cloner, to copy the data between the volumes. So, while resizing volumes is still possible, it has become a multi-step process. Nevertheless, Disk Utility can still resize volumes for you; just plan ahead and be sure to have current backups.
