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donawalt

Contributor
Original poster
Sep 10, 2015
1,354
678
I have a question I have long wondered about...sorry for some of the descriptions as I don't know much about how a disk drive is laid out in Disk Utility!

I am running First Aid on my backup external drive, only because I heard some unique sounds from it that are likely nothing. It seems everything is fine so far, but here is my question - it's a 10TB disk if that matters - In Disk Utility, my backup drive shows as a drive with the name I gave the device, indented under that is a Container, indented under that is the name that Time Machine sees the drive as. I may not even be describing the 1st and 3rd properly, the point is it's 3 lines with successive indentations for the second and third line. I ran First aid on the top line, it finished successfully in about 5 seconds. I am just finishing running First aid on the second line, it has taken about 6-7 hours as it appears to be analyzing every snapshot one at a time (and there are 86 of them) - plus whatever else it's done. So when that finishes, assuming all is ok, is there any value in doing First Aid on the bottom line? If so, is that a long process or short one?
 
Your description of the three levels is correct: Device/disk/drive has one of more APFS Containers, and each container can have one of more Volumes. In your case one container and one volume.

Apple recommends running First Aid on Volumes, then Containers and finally the Drive. See, for example:

And First Aid is slow!!
 
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