How to bring a Time Machine backup to its knees: get it to back up a sparse file to an HFS+ disk. It’ll take forever and run you out of free space.
HFS+
Given their very different structure, backups on APFS disks shouldn’t require routine maintenance. Checking and repair is performed using Disk Utility.
Analysis of the phases of backing up to APFS shows the many similarities with that to HFS+. Crucial differences arise from the use of snapshots as backups.
A blow-by-blow account of what happens when Time Machine in Big Sur performs an automated backup to an APFS volume.
How each of the three different backup schemes used by Time Machine has worked, and how snapshots can work as backups.
How Time Machine has changed since it appeared in 2007, and how backing up to APFS volumes is different now it’s available in Big Sur.
APFS is almost 4 years old, and set out to solve the problem of accumulation of minor errors which has plagued HFS+. Has it?
All about xattrs: their origin, where they’re stored, how they’re named and typed, how to find and work with them, and their common problems.
Explaining inodes, names, dates, permissions, file types, and specialised attributes used for iCloud.
Looking in more detail at newer tricks used by APFS on the data of files: sparse files, which can squeeze vast empty files almost to nothing; file clones; and compression, opening up in Big Sur.
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