Should you Add Volume in APFS?

Home 📂 Blog Posts

Published at: 2018-09-03 10:21:00 +0000


You might be using Disk Utility one day and click on Partition and see this dialog:

disk utility screen shot.png

Don't panic, here is what it means.


Volumes in APFS are like having multiple "mini partitions" inside a real partition, they are all virtual. So it appears like another partition but it is actually sharing the empty space inside the partition that volume was created in.


 | Solid State Drive

 |

 +--+ Partition A (first 1/2 of the bytes on the SSD)

 |  |

 |  +-- Volume X (any of the bytes in Partition A)

 |  |

 |  +-- Volume Y (any of the bytes in Partition A)

 |

 +--+ Partition B (last 1/2 of the bytes on the SSD)

    |

    +-- Volume Q (any of the bytes in Partition B)

    |

    +-- Volume R (any of the bytes in Partition B)


The question is, should you use "Add Volume" with APFS?



Volume

Folder

clonefile to copy instantly

Doesn't work

Works

File permissions

It's Complicated

Normal, just a folder

Same file contents backed by same storage

No

Yes

restore an image on top

Fails when you try

No UI suggests you can


I can't think of any reason practical reason why you would want to add a volume to an existing partition, folders solve more problems and aren't that complicated.


Don't make new volumes! Just make folders instead.





Generated by Max Space

b1VheDeb9rVJTLb8XSVUoQ
gEwSkpHl1y2MDPNQnAYzA=