When you create a backup system for your data, duplication is the best course of action. I do not mean duplicating the files, it is a requirement, but duplication of the destinations to which the files are bound.
All types of backup media are meant to fail, and despite high reliability from cloud backup services, you can not put your faith in that any of them will always be perfect. Even a system of "five nines" of reliability (99.999 percent) can suffer a loss, and the universe can choose you to experience that wallpaper.
The rule of thumb is summarized as 3-2-1
Time Machine has brought this concept back in, but I do not think most people are aware of it, as it is not promoted as such and based on the questions I get from the Macworld readers. Apple makes hay (and rightly so) that it's easy to connect to a drive and answers a question asking if you want to use it for Time Machine backups, and then never have to interact with it again unless you need to recover files.
But macOS also contains support for having more active backup volumes that are used for the same source data at the same time.
- Connect another drive to your Mac. Click Select disk .
- In the dialog that appears, select the new drive under Available Drives and click Use Disk .
- When asked if you want to replace existing Time Machine volume or use both drives, click Use both .
(Checks the encryption backup box in step 3 It's also a good idea because it means that when the volume is not installed, no one else without your password will unlock the disk.)
Time Machine starts A first backup to this volume, which will take as long as the first time you performed a backup with the previous volume. After it's done, macOS switches between the two drives in backup when both are connected.
But here is the best part. Once the first backup is complete, you can separate any of the drives, take it somewhere safe from your home or business, and your Time Machine backup will continue on your remaining volume. As often as every week or two, replace your offsite volume with one place and even if you have a fire, theft or destructive event, you get the almost up-to-date offsite copy.
If you pair this kind of backup with saving important documents using a sync service like Dropbox or iCloud Drive, you will end up being able to recover a Mac that is experiencing a serious crash or someone stolen or losing on a trip to almost the state
Note the formats: Remember that Time Machine volumes – even in High Sierra and Mojave – can not be formatted with the new APFS method that Apple requires for SSDs used as MacOS boot volume. Instead, they must use HFS +. You can format a drive like HFS + in Disk Utility ( Programs > Utility ) by deleting it in the format Mac OS Extended (Journaled) . Erasing loses all the data on the disk.
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