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                 Carbon Copy Cloner Backs Up Cloud-Only Content

   Adam Engst

   When I wrote 'Apple's[1]File Provider Forces Mac Cloud Storage Changes'
   (10 March 2023), I closed the article by noting that backing up data in
   cloud storage services was potentially fraught because online-only
   files wouldn't be backed up. I recommended downloading your entire
   cloud storage data store, at least temporarily, so it would all be
   included in your backup. New files you subsequently created would be
   local and thus backed up, but there are likely situations where files
   created or modified by collaborators would not be properly reflected in
   your backup.

   That is, unless you're using the most recent version of [2]Carbon Copy
   Cloner, which can temporarily download cloud-only content, back it up
   locally, and evict it again to avoid consuming too much local space.
   Agen Schmitz mentioned this feature in his Watchlist item (see
   '[3]Carbon Copy Cloner 6.1.7,' 11 September 2023), but I wanted to call
   it out more explicitly because it's unusual and clever. Bombich
   Software explains:

     When a file stored by one of these storage services is flagged to
     reside only online, the local copy of the file is deleted from your
     Mac and replaced with a 0-byte placeholder file. While this is a
     convenient feature that allows you to free up some space on your
     Mac, this feature imposes a logistical challenge to creating a local
     backup of those files. If you want to have a local backup of these
     cloud-only files, CCC must temporarily download these files to your
     startup disk. CCC can do this, but because this involves downloading
     a potentially large amount of data from the Internet, this
     functionality is disabled by default. Likewise, allowing this data
     to co-mingle with your startup disk's backup could lead to a
     situation where it is impossible to restore your entire backup to
     the original disk due to space constraints. To avoid that,we
     recommend making backups of your cloud-only storage to a separate
     volume on your backup disk.

   The page continues on to provide complete instructions and explain why
   some iCloud-only content still won't be temporarily downloaded (because
   Apple isn't yet using its own File Provider technology for iCloud,
   ironically), among other interesting technical details. It's worth a
   read if you're interested in quirky backup topics or the integration of
   local and cloud storage.

   And, of course, if you're highly concerned about maintaining local
   backups of cloud data, add Carbon Copy Cloner to your backup strategy.

   [4]Read original article

References

   1. https://tidbits.com/2023/03/10/apples-file-provider-forces-mac-cloud-storage-changes/
   2. http://bombich.com/
   3. https://tidbits.com/watchlist/carbon-copy-cloner-6-1-7/
   4. https://bombich.com/kb/ccc6/limitations-online-only-placeholder-files#temp_download

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