Thanks Joe are you familiar with Super Duper though? That's what I'm on for long time and smart updates take an hour or so even though not much changed.
Many years ago I started using CCC as my cloning utility because it was the ONLY one on the market. When SuperDuper out, I switched to it as I preferred SD's user interface. When Apple added the Recovery Drive I switched back to CCC because it handled the Recovery Drive and SD was slow getting on that bandwagon. Both SD and CCC did, and still do, a file-by-file clone which means that even when copying only the changed files, every file on both the Source and Target has to be...
- opened
- compared to see if there has been a change
- If there has been a change copied from the Source to the Target using the regular file replacement routines
- compared once more to be sure nothing went awry in the process
- in the end the clone is verified by once again comparing all the files to be sure they match
That all takes a LOT of CPU cycles and a LOT of disk input and output (the disk input and output takes the most time probably by an order of magnitude or two or three.) All of that is, of course, essential to a complete and accurate clone when it is done file-by-file.
The Apple command line utility that is used in CCC's
Full Volume Clone is a game changer, that was enabled by the structure of the APFS file system, and eliminates most of the processing and all of the file back and forth to essentially a single operation. I seem to recall SD's developer expressing some reservations about it at one point, but that is a vague memory at best and you would have to ask him where he stand on it now. I know CCC has gone through a lot of versions
getting it right, but has worked beautifully for me and I have had zero issues from the beginning.
By-the-way, I don't know if CCC's user interface has gotten better or I have just gotten used to it, but I find it informative and very usable. I prefer the full interface to the simple option.
