External HDs are good for short term backup - I do use them for that myself.
But they are not suitable for long term backup, they are susceptible to damage, sector errors,bit rod and interference.
If you leave them unpowered for longer times the chances that the mechanical components are gonna fail are actually increased.
Some of these issues can be reduced,but never fully.
Additionally there are ransomware viruses that directly attack them - they intentionally encrypt the backups first when the drives are connected before they attack the live data. And in at least one case I know of the attackers bricked the HD firmware.
Therefore for long term storage of really important things WORM (write once read many) media is to be preferred - even if the attackers can access the disk for some reason they cannot alter the once written data.
External HDs are good for short term backup - I do use them for that myself.
But they are not suitable for long term backup, they are susceptible to damage, sector errors,bit rod and interference.
If you leave them unpowered for longer times the chances that the mechanical components are gonna fail are actually increased.
Some of these issues can be reduced,but never fully.
Additionally there are ransomware viruses that directly attack them - they intentionally encrypt the backups first when the drives are connected before they attack the live data. And in at least one case I know of the attackers bricked the HD firmware.
Therefore for long term storage of really important things WORM (write once read many) media is to be preferred - even if the attackers can access the disk for some reason they cannot alter the once written data.