kirsten titus :
Thank you all for replying, I see it is not possible to move the hard drives as they are and expect them to work as before. Will definitely keep that in mind in the, hopefully, far future.
I put the raid together for the sake that I have not done it before and the drives still works, not for any performance gains, the computer is old in any case. I must clarify that no operating system is on the drives, only data.
What I learned is you need 3 or 4 storage mediums if you are on a paranoid level of redundancy to keep your data safe.
1) Your computer HDD(s) / SDD(s)
2) Another computer’s HDD(s)
3) The cloud
4) External HDD(s) stored safely and with no power / not switched on unless needed.
I’ll keep the post open to see if someone else also has a view word to say.
Thank you everyone for your input. Hope this post will serve as a reference to many.
That you only have data on the drives doesn't change the fact that because your drives are setup as a software RAID in RAID 0 (no redundancy) instead of RAID 1 (mirrored drives: redundant) you will have to backup any important data to another storage medium (DVDs, Blu-Rays, another external/internal hard drive) before disassembling your RAID.
As for being ultra paranoid about the safety of one's data; a person would only ever need two drives setup in a hardware level RAID 1 to fully protect their data as it is statistically unlikely that two identical drives will die at the same time (RAID 1 is a two+ drive setup that has identical data on both/all drives (mirrored) so if one dies the other(s) has/have the same data). It is possible to use RAID 5 or 6 where you have distributed parity across multiple drives, however, in RAID 5 you only have safety against one drive failure, so in terms of consumer level redundancy it's basically a more expensive RAID 1; even if it has its advantages. RAID 6 is better than 5 as it has safety against two drive failures, but again, is a lot more expensive than having two or three drives in RAID 1.
External hard disk drives are good, but if you drop one they tend to die. I would either use an external, reliable SSD or try to never move your HDD from where you keep it.
As for the cloud as it is now, it's expensive and I simply wouldn't use it as there is too high a risk of having one's data looked at or stolen.