Found in Sierra, but seems to have fallen into disuse, and not found in High Sierra.
Time Machine
Running High Sierra? Do you keep your Photos Library on an external drive? Do you realise that backing it up using Time Machine is likely to be a waste of time?
Xattr flag to prevent the file or folder (and its contents) from being backed up by Time Machine. Used in Photos Libraries and elsewhere.
As expected, the macOS High Sierra 10.13.2 update contains a great deal more than the three relatively minor […]
Changes include frequent timechecks by timed, harder access to info about keychains, a couple of possible AppleScript bugs, and APFS snapshots.
A post-mortem analysis on attempts to make my iMac dual-boot between Sierra and High Sierra. Can it be done in safety?
When Sierra’s automatic backups stop or become irregular, other functions fail too. Here are some important and more obvious ones. Is this fixed in High Sierra, and does it affect iPhones too?
Does APFS support its major new features – clones, snapshots, etc – yet, and how can you use them?
This new version lets you select which log file to analyse, and to add custom processes to examine within log files. Lots of power with elegant simplicity.
For now, Time Machine can’t back up to an APFS volume. There are many problems with backing up APFS to HFS+, though. Time Machine needs to be revised.
The Eclectic Light Company 