1. How is RAID1 different from a backup copy updated constantly? I am asking this in the context of various comments I encountered in different forums by people saying that RAID is not backup and you must have a backup in place even if you choose to have RAID. For a home user, and ignoring physically separate DR location etc., for a home user, how is RAID1 any different (I can understand why RAID0, RAID5 etc. are different, but RAID1 is just another copy, or is it not?)
2. If I rsync some data from a source to some destination regularly (for backup purposes), I have total control over what gets deleted from source (if at all), what gets deleted from destination (if at all), what gets updated in source and what gets updated in destination etc. But if I use RAID1, how do I determine beforehand what is going to happen? As an example, I want to use a removable SSD as my primary source which I keep updating and this is master copy. If I keep updating it externally, so as to remove and add data from it, when I put it into the computer where it is part of a RAID1 array, what would happen assuming the destination had the latest copy of data before I swapped out the removable ssd, i.e., will the deletions and additions I made in ssd be made in the other RAID1 members as well, or will the deletions I made in ssd get resurrected in ssd? Of course, in case of updates, I expect the updated copies to overwrite the stale copies of data-items and in case of additions, those will get added to the other RAID1 members too.