However, if you've got a backup tape there's nothing from the current that will flip the bits on the tape itself.
There are good reasons to have the backup be off site (other physical calamities) - but the aurora isn't going to flip any bits on a backup. At worst, it will destroy the machinery from a surge from the grid and an extremely powerful one may destroy the machinery from arcing in the device itself (this would be extremely powerful)... but the media itself is fine.
I suspect you’re trying to be sarcastic and/or facetious, but:
Both ideally sure. The more backups and more locations the better. Diminishing returns pretty quickly but why not if the data is important.
Electromagnetic energy from the sun only has a chance of damaging equipment and only some of the bits of that equipment will be affected. You could have two servers in the same datacenter where one gets hit and the other does not. Or even two drives in the same chassis. And even then, it might not be all the data on that drive.
Of course no security is absolute (learned that early from my uncle that owned a convenience store at a lake: He spent extra on doors, locks, windows, etc and someone drove a truck through the brick wall to rob the place). Same here: if a solar event happens that would wipe out all of your onsite and offsite servers “on the surface” then there is a much bigger problem.
> by using ECC memory
ECC protects from bit flips, but aren't high-energy particles required for flipping a bit? AFAIK nothing in the solar wind interaction with our atmosphere can produce them. They'd likely arrive earlier than the wind, but I also haven't heard of gamma ray bursts to accompany solar flares...
> Solar flares are large eruptions of energy coming off the Sun containing several different forms of energy: heat, magnetic energy, and ionizing radiation. The ionizing radiation released during solar flares includes x-rays and gamma rays. These rays of ionizing radiation can damage satellites because they are in space and are not protected by the Earth’s atmosphere. Magnetic energy from solar flares can interrupt radio communication on Earth or damage communications satellites.
Unless you've got a satellite, this likely isn't impacting you.
The last of the risk can be functionally eliminated by your off-site backup.