Hmmm... I'm backing up to a drive that runs only when it's being
backed up to. So that, in theory, would pretty much eliminate the
possibility of simultaneous failure.

Only if it's a different maker, model, or lot number drive. Read my
rant again. One issue that I listed was having two identical drives,
one spinning, the other just sitting on the shelf, fail roughly
simultaneously.

Ouch.


That can happen if the failure is caused by IC
package leakage, board contamination, tin whiskers, or divine
irritation. I only saw this problem once, so I suspect it's rather
unusual. Still, it's something to worry about. These daze, I avoid
running backups to identical drives out of paranoia.

When I bought my current computer in 2001, I bought two identical drives,
and periodically backed up to the second. As I could not, at that time, make
a bootable backup, there was no problem with it running all the time, and I
even added a swap file to the second drive.

Several years ago, when W2K "collapsed" (for unknown reasons), I found that
the backup drive would no longer format. (I don't know why.) The main drive
was put aside, and I suspect it would work if I installed it. (Other than
the time lost reinstalling W2K and the applications, I lost nothing.)

It's frightening when you hear stories of hard drives failing nearly
simultaneously. I've been buying Seagates simply because they have a 5-year
warranty, and I'm not likely to change.

If one of my bootable drives failed, I would immediately (same day) purchase
a replacement and copy the backup drive to it, making the new drive the
primary drive.


Actually, what I'm currently doing for desktops is probably equally
dangerous. After about 4 years running, I buy a bigger|better|faster
drive, mirror the contents of the old drive to the new drive, and then
use the old drive for backups. In other words, pre-emptive
replacement.

What's dangerous about that? Considering how cheap hard drives are, it makes
perfect sense. If you buy two $60 drives every four years, that's $30 a
year -- 60 cents a week. That is cheap protection, and even cheaper
peace-of-mind.