Tag Archives: sierra

APFS Disk Roles

APFS is Apple’s new file system coming sometime in 2017. In 10.12.x the disk management command line tools have been updated to recognize commands relating to APFS. diskutil has some APFS options, one of which being changeVolumeRole . In that verb there is a reference as to how to set the different roles the volume can be

From the manpage of diskutil:

changeVolumeRole | chrole volumeDevice roles
Change the role metadata flag bits of an existing
APFS Volume.

The roles should be any combination of one or more
of the characters busrvBUSRV in much the same man-
ner as diskutil apfs addVolume above, in which
unspecified flags are left alone, use of lower-case
causes flags to be cleared, and use of upper-case
causes flags to be set. Alternatively, clear will
remove all flags, or 0 can be used as a no-op for
scripting convenience. You should not make any
assumptions about the usage or legal combinations
of role bits.

Ownership of the affected disks is required.

But no where does it state what the roles BUSRV are.

The role of the disk can be observed by running diskutil apfs list

APFS Container (1 found)
+-- Container disk2 9C36DEF6-B883-462B-A227-84F8A60E3551
    APFS Container Reference: disk2
    Capacity Ceiling (Size): 255883108352 B (255.9 GB)
    Capacity In Use By Volumes: 138276864 B (138.3 MB) (0.1% used)
    Capacity Available: 255744831488 B (255.7 GB) (99.9% free)
    +-< Physical Store disk0s4 13E393EF-C27E-44EC-B238-A7CA8A842F50     | -----------------------------------------------------------     | APFS Physical Store Disk: disk0s4     | Size: 255883108352 B (255.9 GB)     |     +-> Volume disk2s1 CC9D66C2-345C-4415-92E4-8CDE3A396180
        APFS Volume Disk (Role): disk2s1 (No specific role)
        Name: apfTest
        Mount Point: /Volumes/apfTest
        Capacity Consumed: 24576 B (24.6 KB)
        Capacity Reserve: None
        Capacity Quota: None
        Cryptographic Security: None

Iterating thru the roles they translate to:

B = "Preboot"
U = "User"
S = "System"
R = "Recovery"
V = "VM"

A volume can be set with any combination of roles according to diskutil.

A volume with all roles set shows

APFS Volume Disk (Role):  disk2s1 (Preboot, User, System, Recovery, VM)

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Sierra’s Built-in Storage Management Utility

New with Sierra there is a built-in utility to help keep disk storage space available.  The function is part of the System Information.app and is accessed a few ways:

  1.  => About This Mac => Storage => Manage…
  2. (Hold the option key down)  => System Information… => Window => Storage Mangement (Cmd-U)
  3. /Applications/Utilities/System Information.app => Window => Storage Mangement (Cmd-U)

Once launched it will proceed to gather data sizes of categories of interest. The available and total disk space will be listed in the window’s name.


First you’ll see some recommendations of ways to keep disk space available.  Each has its own set of gotchas so be sure to make note of the implications:

Store in iCloud


There has been some interesting discoveries in the behavior surrounding iCloud Desktop and Documents.  See iCloud Desktop and Documents in macOS Sierra – The Good, The Bad and the Ugly for a full rundown. Even though these checkboxes are checked by default, that doesn’t represent the actual state of the setting.  On my machine I have Desktop and Documents turned off in the iCloud preference pane yet this box shows as checked.

Optimize Storage —


Empty Trash Automatically —


If you’re one of those that can’t commit to deleting things once put in the Trash, let the OS handle it for you.

Reduce Clutter —

This option opens the Documents listing.

Along the left are categories and the amount of space each is taking up.  Accessing those brings up a list sorted by largest on top.  If you want to remove an individual listing, right click and select Delete. Even though Applications are listed, non-admins can’t remove applications without admin credentials.

Thanks to @adamcodega for pointing this tool out.

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