In a Macbook, I'm ready to change the boot disk and replace the superdrive with an SSD. How will Migration Asst work? Use APFS?
Personally, I've lost all faith in Time Machine in recent times.
I'd approach this as a cloning exercise.
I'd go with Carbon Copy Cloner [just because that's the one I know best] &amp; do as your 2nd suggestion.
Clone to the DVD replacement, test, add the new larger SSD in place of your old HD, clone again. Remove [or just temporarily disconnect] the 1st SSD to test again.
If all is successful, wipe the intermediate SSD. If at any point something goes wrong [which barring human error it shouldn't] - you still have the original HD as belt &amp; braces.
Once finished, neither you, your software, or your sql will know the difference.
One final check once you're done - open System Preferences &gt; Startup Disk &amp; make sure the new boot drive is already selected [it should be, but I've known it miss very rarely]
One thing to note when cloning:
Rename the new drive to something else first, so you will then be cloning MyDrive to MyDrive Clone.
Once the clone is complete &amp; you are sure you can boot to it, change the names again, to MyDrive [from MyDrive Clone] &amp; MyDrive Old [from the original]
This
a) makes sure you don't lose track… or indeed your sanity &amp;
b) keeps anything that was reliant on the drive name sane too.