Honoring com_apple_backup_excludeItem on MacOS

filters
backup

#1

On MacOS an extended attribute com.apple.metadata:com_apple_backup_excludeItem is used to tell backup software that the particular file does not need to be backed up. This is a more robust solution compared to separately maintained global exclusion list as the metadata is kept physically close to the the data it describes; that way applications, who have much better idea about how to manage their files, can decide what gets backed up and what is transient and shall be skipped.

Example:

myimac:~ me$ touch testfile
myimac:~ me$ ls -alt@ testfile
-rw-r--r--  1 me  staff  0 Jul 10 12:38 testfile

myimac:~ me$ tmutil addexclusion testfile

myimac:~ me$ ls -alt@ testfile
-rw-r--r--@ 1 me  staff  0 Jul 10 12:38 testfile
	com.apple.metadata:com_apple_backup_excludeItem	61

myimac:~ me$ tmutil removeexclusion testfile

myimac:~ me$ ls -alt@ testfile
-rw-r--r--  1 me  staff  0 Jul 10 12:38 testfile

myimac:~ me$

For more info see man tmutil

Time Machine honors that flag, as does CrashPlan and even Arq.

Duplicacy should too.


Do not filter out .duplicacy/ and change transient data locations
Exclusions using StdExclusions.plist and com_apple_backup_excludeItem metadata in duplicacy?
How to create a superset of an existing back-up repository without re-uploading data?