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Archive for May 15th, 2018

by Tom Nelson

Disk Utility has long been the workhorse of choice for dealing with hard drives, SSDs, and disk images. With the advent of APFS (Apple File System) with macOS High Sierra, Disk Utility acquired some additional capabilities that allow it to work with APFS and its support for containers.

DiskUtilityIcon

We’re going to look at how to use Disk Utility to partition drives into multiple containers, and how to add volumes to containers. If you need to partition and manage standard HFS+ volumes, you’ll find detailed instructions in the Rocket Yard guide: How to Use macOS Sierra Disk Utility to Partition, Erase Drives.

What Are Containers?
Containers are a new abstract used in the APFS system to define a storage system that can share available free space among one or more volumes. Apple calls this Space Sharing. It allows volumes that are within a common container to grow or shrink as needed, without any type of repartitioning.

Containers, then, define a block of space on a physical drive that will be assigned to and used by volumes you create in the container. Volumes you create in a container can have a minimum size and a maximum size, but the actual amount of space they use is dynamically assigned from the container’s free space, as each volume within the container needs the space.

The selected drive shows that it contains two containers of different sizes. The smaller container houses a single volume, and the larger container holds two volumes. Screen shot © Coyote Moon, Inc.

Use Disk Utility to Create an APFS Container
Containers are only supported on drives formatted with APFS. You can format a drive or convert an HFS+ drive to APFS using the version of Disk Utility found in macOS High Sierra or later.

APFS was designed primarily for use with SSDs, though it should also work with standard hard drives. But before you decide to format a hard drive to use APFS, you may want to read: Using APFS On HDDs …And Why You Might Not Want To. At the moment, Apple doesn’t support APFS being used on Fusion drives.

Before you begin this process, take a moment to make sure you have a current backup of the information on your Mac, and that the drive used for backups isn’t one of the drives that will be involved in any of the processes we will be performing. The best way to do that is to eject the backup drive and, if possible, disconnect it from your Mac.

With your backups current, you’re ready to explore the APFS file system, including working with containers and volumes.

Launch Disk Utility, located at /Applications/Utilities.

In the Disk Utility toolbar, click on the View button and select Show All Devices. You can also use the View menu to perform the same task.

To convert an HFS+ volume to an APFS volume, select the HFS+ volume on the Disk Utility sidebar. (HFS+ volumes appear just below the physical drives in the sidebar.) Once selected, choose Convert to APFS from Disk Utility’s Edit menu. A sheet will drop down asking if you would like to convert the drive to APFS. Converting to APFS shouldn’t cause data loss on the selected drive, but it’s a good idea to make sure the data on the drive has been backed up first. When you’re ready, click the Convert button.

Disk Utility being used to convert the existing Video volume to APFS. Screen shot © Coyote Moon, Inc.

To format a drive in APFS, select the drive in Disk Utility’s sidebar. Select Erase from the toolbar or from the Edit menu. Provide a name, and then select one of the APFS formats from the Format dropdown menu. Formatting a drive will erase all of the data it contains, so make sure you have a backup of the data, if needed, before proceeding. When you’re ready, click the Erase button.

Disk Utility will create an APFS container, along with a single volume within the container.

Read more on Rocket Yard, The MacSales.com Blog

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