Question about RAID10

Question

linux

A software raid 10 was assembled from two raid 1, each of which in turn consists of four disks. mdadm --detail outputs one raid at a time

State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0

and for the second array

State : active
Active Devices : 2
Working Devices : 4
Failed Devices : 0
Spare Devices : 2

In connection with what could this be, the array is working normally, it does not fail, but the system marks two disks in one of them as spare?

Answer 1

And show me cat /proc/mdstat.