Does Big Sur’s Time Machine preserve sparse files and clones when backing up to APFS volumes?
backup
It’s common to want or have to change either the source or destination disk for backups. How well does Time Machine to APFS cope with that?
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.
Given their very different structure, backups on APFS disks shouldn’t require routine maintenance. Checking and repair is performed using Disk Utility.
Until Big Sur started backing up to snapshots on APFS, there was little interest in being able to copy snapshots. Now we realise that we can’t.
Unlike HFS+ backups, those on APFS volumes look different depending on how you try to access them. What you see in the Finder is an illusion not available to other apps.
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 can you check the integrity of important files you have stored in iCloud, or in a Time Machine backup, such as those made by Big Sur to APFS?
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