Will copy/pasting the known good data directory to the corrupted one solve the corruption problem? Is it as simple as re-booting and starting fresh with the one exception that the new program will have to re-build to the current height?
Yes. That's how any backup works. It's probably best to shut down Bitcoin Core before you start making your backup, you shouldn't copy it while it's being written to.
IF AND WHEN that time comes, when I have to re-paste in the entire data directory (Bitcoin), I just hope that there will be no errors with permissions. Come to think of it, in Roaming I have some programs I never use. I could test one in exactly the way I would do with Bitcoin . . .
In spite of having a UPS and an AC/DC inverter for the house, I am now on IBD #3
How did that happen? For what it's worth: I prefer a laptop over the hassle of getting a UPS.
A BUNCH of stuff happened. First, I found out that the battery in my UPS was dead and not charging. I am very ambivalent about UPS's: a. You also need to connect your monitor which uses more power, b. You only have some minutes to shutdown and we can't be at our computers 24/7, c. manufacturers make it difficult or impossible to replace the battery. You are forced to re-buy and replace a perfectly good UPS. Second, after the second day of a power outage, we took the inverter to zero charge. When we re-charged it, the charge was unstable and it shut down. Lastly, I generally run Linux. I loathe Windows. I use it because I must to run graphics software for my microscope, so I use the Windows computer for my projects. Sometimes Windows shuts down improperly. It's a tremendously buggy OS.
a. Copy/paste or delete old and replace new?
When restoring a backup, I wouldn't want to keep incomplete newer block files while restoring older files. If you have enough disk space, you can rename the damaged directory before restoring your backup. If you need it again, at least you still have it.
IT OCCURS TO me that a copy/paste of new over corrupted would be a mistake. The chance for errors is to great. I do a lot of copy/pasting of music data. Sometimes the process chokes and I get an option to "skip" and continue. That could be fatal for something as precise as the blockchain. I think it'd be better to delete the old good backup and re-write using the known good . . .
b. Ditto EXCEPT do this only with the blocks subfolder?
If your wallet isn't corrupted, you shouldn't replace it. Your backup won't have the latest transaction Labels.
I DON'T USE the wallet. A CLI wallet (for me) is not the place to practice. I use a cold wallet and run the Core to support the blockchain.
the data increasing roughly every ten minutes, you would need to do a backup frequently
If you're a month behind, you'll only need to sync a few GB. If that's acceptable, you don't need very frequent backups.
TRUE. I'm thinking once a week or so. I happend to have a 2TB external drive which I'm reserving just for that purpose. And yes! SHUT DOWN THE CORE before copying!