Running Raspbian on RPi 2B:
Perhaps foolishly I've chosen the RPi for a significant development that needs much more than its internal flash storage, so have attached a terabyte USB drive as sda1. During power-on boot the following is reported:
[10.872768] sd 0:0:0:0 [sda] 1953525168 512-byte logical blocks: (1.00 TB/931 GiB) / failed
This is despite the following line having been inserted to /etc/fstab:
/dev/sda1 /mnt auto defaults,exec 0 2
Thereafter the drive cannot be accessed except by performing a commanded mount. Or a reboot. Obviously the problem occurs because the Western Digital "Bookcase" drive becomes operational from power-on slower than the RPi. A few seconds "sleep" added to the boot process almost anywhere before that failure would synchronize the two.
The question is, where and how to issue the sleep? Progress through the Raspbian boot sequence scripts in
/etc is not at all clear.