xattr: com.apple.metadata:com_apple_backup_excludeItem, exclude from backups

Type: com.apple.metadata
Subtypes: com_apple_backup_excludeItem
Serialisation: none
Data type: binary property list usually containing com.apple.backupd as a single NSString.
Example: <62706c69 73743030 5f101163 6f6d2e61 70706c65 2e626163 6b757064 08000000 00000001 01000000 00000000 01000000 00000000 00000000 00000000 1c> «bplist00_ com.apple.backupd »
macOS: Sierra, High Sierra
System use: only for /private/var/db/CoreDuet and com.apple.AssetCacheLocatorService/diskCache.plist in /private/var/folders/
App use: none
Document use: some items within iMovie Library, iTunes docs, iPhoto Library, Aperture Library, and Photos Library
Other usage: extensively in ~/Library, especially for session docs and caches

Purpose: effectively adds the item (folder and contents, or file) to Time Machine’s exclude list
Used in specific locations to ensure that files and the contents of designated folders are not backed up by Time Machine.

I don’t know whether this is respected or used by other backup software.

Could possibly be used by user to prevent backup, but the binary flags would need to be deciphered before this became reliable. The first section appears identical in each use:
<62706c69 73743030 5f101163 6f6d2e61 70706c65 2e626163 6b757064>
and the remaining content is almost always
<08000000 00000001 01000000 00000000 01000000 00000000 00000000 00000000 1c>

Rarely, may just be
<636f6d2e 6170706c 652e4d6f 62696c65 4261636b 7570>

which may exclude from Mobile Time Machine rather than regular backups.

In High Sierra, Apple has warned users not to use Time Machine to back up Photos Libraries on external drives. Could this be related?

Tools: xattred, xattr


Original page: 2017-12-12
Last modified: 2017-12-30