I have RAID 5 on 3 hard disks, in which one of them is external on USB 3. I'm facing problems on boot because sometimes the external drive isn't detected or maybe isn't ready soon enough, and the RAID starts in degraded mode. Its usable after startup but in degraded mode. Sometimes Ubuntu gets stuck on BusyBox and I have to exit for it to continue booting. After boot when I check the
mdstat file it says the drive is missing. Then I manually add the drive using
mdadm --manage --add command and then it starts reconstructing the array putting load on my CPU.
Is there a way I can prevent Ubuntu from assembling the array when its not able to detect drive in the RAID?