Disk errors threaten your data: how to detect them, how to use First Aid in Disk Utility, how to use fsck, and what to do with the disk afterward.
APFS
Where to look for file metadata in the Finder, and how you can customise it, in spite of its apparent confusion. And how APFS takes care of extended attributes for you.
From its outset, APFS hasn’t tested the integrity of file data stored on it. Would this be a good idea, or should macOS switch to the ZFS file system instead?
New version of this GUI utility for inspecting and editing extended attributes, for High Sierra and later.
How can you have two volumes in the same APFS container with identical names? How does macOS handle the conflicts?
How does copy on write work, and how do clones grow apart? What effect do they have on the use of space and performance?
Similarities and differences, how to make each in the Finder and Terminal, how much space they use, and how they work in APFS.
After studying thousand of log entries in less than 2 seconds, this is how macOS updates its values for purgeable and available space. But who uses them?
Deleting two large files from a volume triggered the updating of figures for purgeable and available space within 9 seconds. Yet 6 minutes later, the Finder didn’t show those updated figures.
One volume has 60 GB of purgeable space, giving 295 GB available; the other has only 15 GB purgeable, so 250 GB available. How can they be in the same container?
The Eclectic Light Company 