Therefore, in light of my new best practices, let me just ask you one last thing, just to see if I'm getting this backing up methodology down... I'm thinking of doing the following, 3 HDDs:
Main drive in the computer - A
Second drive in another bay, powered, connected - B
Third drive, offline, not in computer at all - C
I don't write to A enough to warrant daily updates/backups, but I'd say twice a month couldn't hurt. Plus, if any particular week I get tons of tagging done, then it would prompt an in-between back up just to update all that work. (with discographies, this can get heavy)
Just offhand comments on previous posts...
WD Reds are OK. I got one (the original was bad OOB, by the way; WD replaced it with a bigger one, which is still in use) in my HTPC, it works just as well as any of the other drives I have. It's been rotated to backup files, so it doesn't really see that much read use any longer.
If I lost my main HTPC storage drive, a 5TB Toshiba, I have a backup of all the valuable (to me) files across two separate 3TB drives... even though I still have the source material. However, like you mentioned, those files represent 100's of hours of labor ripping, tagging, and properly filing... something that I'm not anxious to do again.
I use portable drives on my main desktop... because if the house catches on fire or thieves steal my PC, I have a reasonably current copy of my OS stored securely elsewhere... away from my PC. A portable drive is the easiest way to do this. Yes, you can use HDDs in a hot swap bay or something, but then you are fooling with a bare drive... in my mind not a good idea.
One or two backup drives in the PC itself are there as a current backup (and, in the case of a 2nd drive, a backup to the backup...) I think Acronis will make incremental backups, either as you go or on a schedule (say, every morning at 2AM when the computer is idle, etc.) Personally, I just make full images every night, approximately a 200GB file, of my OS drive.
In your case, where you are trying to maintain a backup of a large amount of data (not necessarily an OS drive like me) I would have Acronis do
incremental backups every night to your internal drive(s,) and a
full backup to whatever external source(s) you have, say once a week, and manage at least 2 separate external drives in some sort of rotation to guard against loss or damage.
Backups are important, don't get me wrong... just don't overthink it. Keep it simple, it's more likely you will continue to use it if it doesn't require continual effort... like pulling hard drives out of the computer. With the system I outlined above all that is required of you is to swap a USB-powered external drive out once a week or two, and, of course, validating the backups that are generated.