ops, sorry the first swapon was a typo (control v) sorry, i know using
the swapon lock device, only swapoff and after a mdadm --create could
work in this case, but remove the first swapon... just mdadm create,
and swap over md device is the point here...

the /dev/sda and /dev/sdb was just examples, they can be partitions
without problems

the point is: using swap at two partitions / disks, is "better" than
using a swap over a md raid1? (or any other level?)
other point is... swap have a badblock feature? i think it's not
linux-raid but linux-vm or something like it...
for example if i'm using a disk and swap find a badblock, it will use
it? does swap handle bad blocks? it remove the device? continue using
it? or change the device priority?