Is it possible to change the composition of partitions to RAID1?

Question

linux

There is a RAID1 (3 SSD) consisting of two partitions: the first one is /dev/md0 ext4 28Gb (it has Debian 9 installed) and /dev/md1 xfs 204Gb (empty). Is it possible to split the /dev/md1 partition into 12 17Gb partitions without reinstalling the system?

Answer 1

Yes.
Unmount, create the required number of partitions, merge into mirrors, mount.