Raid 0 problems

Hello everyone!

I’m using a rpi4 with dietpi and the quad sata hat. I can see all my drives in dietpi drive manager.

I’m trying to create a raid 0 array. First I create a partition with gdisk then I create the array with mdadm. I can see it in dietpi drive manager. Then I use the drive manager to format and mount the raid device. Everything is going well. I can write and read files on the raid device.

When I reboot the rpi, first mdadm tells me that the array is CLEAN, but when I try to write a fie on it, it becomes FAILED… I’m not able to see the raid device in dietpi drive manager, and all my disks (/dev/sd[a-d]) disappeared…

Am I doing something wrong?

Thanks in advance