[SOLVED] USB HDD boot fail, "!! Could not find the root..."

[jcc3]

This problem has been mentioned in several threads; I started one of them some months ago. Best synopsis here:

https://forums.gentoo.org/viewtopic-t-828155.html

I use an initrd because the system on this USB HDD is in a specialized laboratory environment, with some unusual requirements.

This problem occurs regardless of whether device or UUID is used as the argument if real_root, and in my case (and probably the others) the root cause appears to be a race condition between the slow USB drive's wake-up period and linuxrc invoking findfs( 8 ).

Solution: All suggestions (there were many) failed to solve the problem, until author NeddySeagoon suggested adding a sleep in linuxrc at the right place(s). In my case, a sleep of 10 seconds just before the requisite findfs( 8 ) in linuxrc was the answer.

There was always a simple workaround for this problem: just manually replying to the "Could not find" message. But the solution presented here allows unattended boot, which I need.

[For reference, the USB HDD model in question is a Maxtor "One Touch 4 Mini" 160GB drive, P/N 9NU2AH-500.]

[BradN]

I'll add in that if one experiences this problem when NOT using an initrd, the rootwait kernel option will make the kernel wait forever until the root device shows up, solving this problem for USB drives.