Configure Custom Exclusions using XML (Mac)

Exclusions prevent all files and subfolders of a directory from being indexed or included in a Backblaze backup.

Changes were made to the Backblaze Computer Backup Mac client in version 4.1 and newer that make it easier to determine what is excluded and to set custom exclusions other than the standard folder, file size, or file type options.

In the new system, some exclusions are mandatory, including operating system files and program files. These exclusions are in the file named bzexcluderules_mandatory.xml located here: /Library/Backblaze.bzpkg/bzdata.

You can view this file with a text editor, and it contains the permanent exclusion that Backblaze uses.

Exclusion Rules

You can edit the file bzexcluderules_editable.xml to create more robust rules to exclude data. To restore the defaults, you can remove the file. It returns when you perform your next backup.

• The excludefname_rule variable is case insensitive.
• A file must match all of the criteria on the line to be excluded from backup.
• An excludefname_rule variable must specify all criteria. Use "*" to skip criteria.
• The skipFirstCharThenStartsWith variable is "*" or must be at least four characters long.
• All of the rules apply to all attached volumes. This means that all rules are applied to / and also /Volumes/externalUsbDrive/ and /Volumes/movies/, etc.

Valid Operating System Versions (osVers)

• 10.9
• 10.10
• 10.11
• 10.12
• 10.13
• 10.14
• 10.15

hasFileExtensiom versus endsWith: A "file extension" in this context is strictly defined as the last period followed by non-space, simple ASCII characters, and it does not contain a forward slash (/) or backslash (\). The endsWith is more general in that it can have spaces and include either slash. The hasFileExtension is faster and helps the code group the same file extensions together, so you should specify the hasFileExtension, if possible.

Performance Hints

Always specify a skipFirstCharThenStartsWith. It is very performant and assists with pruning 99% of files from undergoing additional criteria checks.

Internally, the code groups together many tests with identical startsWith and skipFirstCharThenStartsWith, so those comparisons are done only once (not once for each excludefname_rule).

Next, you should specify hasFileExtension if possible, or if not, then define endsWith which results in faster performance than contains_1 and contains_2.