what to know
- Go to Applications > Utilities > Disk Utility > the drive you want to change.
- Press Partition > Partition .
- Resize the volume as needed by dragging the pie partitions or deleting existing volumes.
This article explains how to resize a volume using Disk Utility in macOS.
Partitioned Fusion Drives can only be resized using the version of Disk Utility originally used to create the Fusion Drive or later. For example, if your Fusion Drive was created using OS X Yosemite, you can resize the drive using Yosemite or El Capitan, but not any earlier version.
You can enlarge a volume as long as it is not the last volume on the drive. You must be willing to delete volumes and their data that are behind the volume you want to enlarge.
Make sure you have an up-to-date backup of all data on the drive you plan to modify. Here's how to amplify the volume.
Start Disk Utility, located in Applications > Utilities .
Alternatively, type "Disk Utility" into Spotlight search to quickly launch the application.
Disk Utility displays a two-pane interface. Select the drive containing the volume you want to enlarge.
Select Partition from the Disk Utility toolbar.
If the Partition button is not highlighted, you may not have selected the base drive but one of its volumes.
Select the partition again to confirm.
You will see a pie chart of all volumes contained on the selected drive. You will see the available free space and the space occupied by each volume.
To make one volume larger, you need to delete the other volume. Select the volume to delete by clicking once in the pie chart. The selected pie slice turns blue and the name of the volume appears in the Partition field. (In this example, we select and delete the volume More Stuff .)
Click the minus icon at the bottom of the pie chart to delete the selected volume. A partitioned pie chart shows you the expected results of an operation. Select Apply to continue, or Cancel to stop making these changes.
If you apply the changes, the freed space will be added to your remaining volume.
You can also use pie dividers to resize pie slices, but be careful; if the slices you're resizing are small, you may not be able to grab the dividers. Instead, select the small pie chart and use the Size field.
It would be nice if you could resize the volume without having to delete the volume and lose any information stored in it. With the new Disk Utility, this is not possible directly, but under the right circumstances you can resize without losing data, albeit in a somewhat complicated way.
For example, there are two volumes on the drive you selected: Stuff and More Stuff. Stuff and More Stuff each take up 50% of the drive space, but the data on More Stuff only takes up a small portion of its volume space.
You can expand "something" by reducing the size of "more stuff" and then adding the now available space to "things". Here's how to do it:
Make sure you have up-to-date backups of all data on Stuff and More Stuff.
Start Disk Utility and select the drive containing the Stuff and More Stuff volumes.
Select Partition from the Disk Utility toolbar.
Select the "More Content" volume from the pie chart.
Disk Utility allows you to reduce the size of a volume as long as the data currently stored on the volume still fits in the new size. In this example, we reduce "More Content" to 45 GB. Next to Size , enter 45 GB and press Enter or Return .
The pie chart shows the expected results of this change. Select Apply to commit the new partition.
Select a partition to confirm. In the next section, we will add the freed space to Stuff.
Now we add the newly freed space to "Stuff".
Select the untitled volume you just created and select Restore .
Next to Restore from , select More , and then select Restore .
The recovery process may take several minutes. When finished, select Done .
Now we will complete the volume resizing process.
Select the drive containing the volume you have been using and select Partition .
In the partition pie chart, select the More Stuff volume used as the source in the previous section and select the minus button to remove it, adding its space to the Stuff volume.
More Stuff data will be restored to the remaining volumes. Select "Apply" to complete the process.
Click Apply to complete the process.
Understanding how resizing works in Disk Utility will help you resize your volume without losing any information.
- When expanding a volume, the volume or partition immediately following the target volume must be deleted to make room for the expanded target volume.
- The last volume on the drive cannot be enlarged.
- The pie chart interface for adjusting volume is finicky. If possible, use the optional Size field to control the size of the drive segments rather than using the pie chart's dividers.
- Only drives formatted with a GUID partition map can be resized without data loss.
- Before resizing a volume, be sure to back up the drive's data.
As you can see, resizing with new versions of Disk Utility can be simple, as shown in the first example, or complex, as shown in the second example. In the second example, you can also use a third-party cloning application, such as Carbon Copy Cloner, to copy data between volumes.
So while resizing a volume is still possible, it has become a multi-step process. Still, Disk Utility can resize the volume for you; just plan ahead and make sure you have up-to-date backups.
