USB and boot failure because of randomly missing partitions in /dev

Hello,

I'm having the following issue : randomly, when booting or rebooting my nas (intel NUC + 4-disks icybox USB3 bay) some of my drive's partitions are missing (/dev/sdb is there, but not /dev/sdb1).
If i enter maintenance shell and re-probe my drive (hdparm -z /dev/sdb) then the partition appears (!).

I'm feeling this is an issue with the spin-up of my disks, because for whatever reason (usb re-init after bios ?), just after GRUB all my disk spin down then up, one by one (probably a sequence internal to my bay), and at that moment systemd mount scripts are waiting for my partitions to appear. Some are detected, but most of the time, at least one is not then the script times-out after 1min30 and boot sequence fails.

Has anyone ever heard of such an issue ?

Is there a way to insert a pause at boot just before the partitions mount, in order to give my disks more time to spin up ?

Thanks in advance,

Luckily I might have found the solution just after writing this post (had better google keywords ?).

Anyway : the kernel option "rootdelay" might do the job !

I added a 30s delay before mounting root partition so that my usb disks have enough time to spin up, and it seems to be OK.

I'll wait some time and put the thread as OK once it proves to be stable !