Is it possible to create RAID10 on data drives?

Question

linux

There are 12 disks on the server, now in total they are slightly less than 50% full.
The question is, is it possible to transfer all data to 6 disks,
and make the remaining 6 free and organize a RAID10 array?
Or is it necessary to format / reinstall everything?
There is simply nowhere to put the data temporarily, which is why it is possible to create a raid on a working machine.

Answer 1

RAID10 = RAID1 x RAID0 (yes, that kind of weird math).
RAID1 is assembled from non-RAID without problems. To do this, when creating a RAID, you need to specify a partition with data as the first mirror, and an empty partition as the second (regardless of their physical and logical numbers). Then launch the array rebuild, which will start the restoration, which will flood the second mirror with the contents of the first one. I personally did this a few years ago, everything worked fine, I don’t remember the exact sequence of commands (I haven’t been in administration for a long time), but there are manuals where everything is written.
But RAID0 from non-RAID is not so easy to assemble. There is no way to do without backup / restore. But since you have 6 pairs of disks, you can backup them one by one, convert them to an array and restore them.