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Configuring filters to limit what is backed up

 

Typically when you clone your hard drive to another drive, you want to copy everything. When you perform regular incremental backups, however, space becomes an issue. Filters allow you to specify what items on your hard drive should not be copied to the backup device when using the "Incremental backup of selected items" cloning method. A filter is created automatically for you when you uncheck items in the "Items to be copied" table. More advanced filtering options are available as well, including the ability to exclude items based on file type and the ability to specify your own rsync-compatible rules.

Creating filters

Creating your own filters is a breeze. Simply choose a source volume in the Source Disk popup menu, then start deselecting items that you do not want to copy. As you deselect items, the default filter for that volume is updated with your selections. To view and edit the filters that you have created, click on the "gear" popup menu next to the Source Disk popup menu. [If this button is disabled, select a source volume from the Source Disk popup menu.]

Configuring Remote backup

In the Filter Settings window, you see a list of filters on the left and the contents of those filters on the right. Every time you choose a volume from the Source Disk popup menu, a filter is created for you with a name in the form of "Source Disk (Default)". As you deselect items to be copied, those items are added to the filter. When you quit CCC, the filters are saved and available the next time you launch CCC. Whenever you choose a volume in the Source Disk popup menu in the future, the settings from the default filter for that volume will be applied.

Customizing filters

Typically you will not need to manually configure your filters. If you would like to maintain more than one filter for a particular volume, or if you would like to apply more advanced settings such as file type filters, then you do so in the Filter Settings window. To create a new filter, click the "+" button and provide a name for the filter. To remove a filter, select the filter in the Filters table and click on the "-" button. If you delete a default filter for a volume, that filter will be recreated the next time you select that volume in the Source Disk popup menu.

To delete items from a filter, select the item(s) from the "Items you have excluded..." table on the right and click the "-" button or press the delete key.

Advanced filter options

If the files you want to exclude are scattered across your filesystem, it may be tedious to manually exclude each of them. To address this, CCC implements file type filters. File type filters allow you to specify a file extension (e.g. "dmg", "doc", "mp3", etc.) of a file type that you would like to exclude. Suppose you want to exclude disk images from being backed up, for example*, simply add "dmg" to the File types filter table and any file with that extension will be excluded.

For the truly adventurous, CCC permits the definition of custom rules. These custom rules follow the syntax defined in the rsync man page. Using the rules in the screenshot above as an example:

- Library/Caches
- /private/var/log
- /Library/Logs

The "No logs or cache" filter will exclude any item that contains "Library/Caches" *anywhere* in the path (for example, ~/Library/Caches in every users home directory as well as in /Library/Caches). Items in the /private/var/log folder at the root of the volume will be excluded as well as items in /Library/Logs (but not, for example, in /Users/mike/Library/Logs). Note that in the case of /private/var/log, you must indicate the real path of the directory to be excluded. Indicating the /var/log symbolic link, for example, would not be sufficient to exclude the contents of this directory.

If you would like to override one of the default exclude rules set by CCC, create a new rule with a "+" prefix. For example, to include the contents of any Trash folders, use this custom rule:

+ .Trashes

You can learn more about custom rules by reading the "EXCLUDE PATTERNS" section of the rsync man page.

Note: Filters specified in the "Advanced options" section of the Filter Settings window will not be reflected in the "Items to be copied" table in the main window.

Suggested additions to your custom filters

As indicated above, read/write disk image files should be excluded from an incremental backup regimen unless they are infrequently used. By examining many months of backups, I have discovered that the following "disposable"items also consume too much space on my backup hard drive:

Items automatically ignored

Carbon Copy Cloner excludes some items from the backup task by default. A complete list of exclusions along with an explanation for the exclusion is available in this section of the documentation.