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Using two drives with Time Machine?
- Thread starter kat.hayes
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I actually stumbled upon this answer a few days ago accidentally. You do it with a super hidden secret of SuperDuper. It will work the same way though....
From : ( http://www.shirt-pocket.com/forums/archive/index.php/t-1186.html )
... a little program called SDDiskTool that's inside the SuperDuper bundle you can use to set the UUID. It's in SuperDuper!.app/Contents/MacOS/SDDiskTool. You'd use:
SDDiskTool -g /Volumes/some-disk-name
to get the UUID. Then, to set it, you'd use:
sudo SDDiskTool -s the-UUID /Volume/some-other-disk-name
So, pick the one you want to be the original, and set the other UUID to be the same. At that point, we're going see any of them as the same drive... so you can swap them at will.
So, that should make both drives have the same UUID, and you can do that. Just try not to have both drives plugged in at the same time, as that may cause an issue.SDDiskTool -g /Volumes/some-disk-name
to get the UUID. Then, to set it, you'd use:
sudo SDDiskTool -s the-UUID /Volume/some-other-disk-name
So, pick the one you want to be the original, and set the other UUID to be the same. At that point, we're going see any of them as the same drive... so you can swap them at will.
It is easy to do. Plug in the second hard drive you can want to use for backup. In the Time Machine preferences select add a drive, browse to the second hard drive and add it. You will be asked whether you want to replace or use both, select to use both. Now Time Machine will backup to both hard drives. You can even eject the new hard drive and store it away. When you plug it in, select backup now and Time Machine will backup to the new hard drive. Eject it and store it. This is how I do secondary Time Machine backups. If you leave the second hard drive connected Time Machine will backup to each every hour. So it does not require you to leave it connected all the time. Time Machine will even notify you if you have not connected the second hard drive for more than 10 days. So it is a nice reminder feature. Hope this helps.
if you leave both drives in, Time Machine will alternate back and forth each hour.
This is what I do. I have two TM drives and let macOS back up to both.
I do roughly the same thing. I have one 4TB drive permanently connected, and two 3TB drives which are swapped over every week when my father in law comes round for his Sunday dinner. He keeps the spare' off-site for additional safety.