initramfs don't find my root block device

Olaf35 · 10-05-2014, 05:01 AM

Hi,

I've got an externel hdd with a gentoo linux. I can plug this hdd to multiple different Laptops and PCs and can use gentoo. On one Laptop I can boot fine, my root block device is detected (UUID=a97c2681-5124-4749-baf0-dc65031460a8) to /dev/sdb1. These Laptop don't have a CD/DVD device. On other Laptops the detection fails. I got the message:

>>Determining root device...
!! Could not find the root block device in UUID=a97c2681-5124-4749-baf0-dc65031460a8
!! Please specify another value or:
!! - press Enter for the same
!! - type "shell" for a shell
!! - type "q" to skip

If I type "shell" and "exit" to exit the shell the system boots from the correct device /dev/sdb1 or (/dev/sdf1 on another PC). The same happens if I type "q".
The differences of these Laptops/PCs are, that they have got a CD/DVD drive.

The system boots with grub2 with an initramfs.

How can I fix it?

Drakeo · 10-05-2014, 05:49 AM

]I think your problem is your bios settings. but it would be nice to see if a f12 or f8 or f10 functions bring up a menu for devices to boot from. and I would check my bios to see where that device is placed. now I have also edited my grub a few times to actually read root=/dev/sdx and then edited my /etc/fstab to be the same.

Why ? so it does not have to scan all it has to do is look for that device not read a blkid.
you can make a few different grub entries some with blkid some with out.

Olaf35 · 10-05-2014, 02:41 PM

Hi Drakeo,

thank you for your reply. On the PC I have to press the F8 key for the boot menu and on a laptop it is the F10 key. In both machines the CD/DVD drive will be prefered in the boot sequence.

By changing the root or real_root entry in grub2 doesn't help.

The message comes from the init script inside my initramfs ramdisk.

...
# Determine root device
good_msg 'Determining root device...'
while true
do
while [ "${got_good_root}" != '1' ]
do
case "${REAL_ROOT}" in
LABEL=*|UUID=*)

ROOT_DEV=""
retval=1

if [ ${retval} -ne 0 ]; then
ROOT_DEV=$(findfs "${REAL_ROOT}" 2>/dev/null)
retval=$?
fi

if [ ${retval} -ne 0 ]; then
ROOT_DEV=$(busybox findfs "${REAL_ROOT}" 2>/dev/null)
retval=$?
fi

if [ ${retval} -ne 0 ]; then
ROOT_DEV=$(blkid -o device -l -t "${REAL_ROOT}")
retval=$?
fi

if [ ${retval} -eq 0 ] && [ -n "${ROOT_DEV}" ]; then
good_msg "Detected real_root=${ROOT_DEV}"
REAL_ROOT="${ROOT_DEV}"
else
prompt_user "REAL_ROOT" "root block device"
got_good_root=0
continue
fi
;;
ZFS*)
if [ "${USE_ZFS}" = '0' ]; then
prompt_user "REAL_ROOT" "root block device"
continue
fi

ROOT_DEV="${REAL_ROOT#*=}"
if [ "${ROOT_DEV}" != 'ZFS' ]
then
if [ "$(zfs get type -o value -H ${ROOT_DEV})" = 'filesystem' ]
then
got_good_root=1;
REAL_ROOT=${ROOT_DEV}
ROOTFSTYPE=zfs
else
bad_msg "${ROOT_DEV} is not a filesystem"
prompt_user "REAL_ROOT" "root block device"
got_good_root=0
continue
fi
else
BOOTFS=$(/sbin/zpool list -H -o bootfs)
if [ "${BOOTFS}" != '-' ]
then

for i in ${BOOTFS}
do

zfs get type ${i} > /dev/null
retval=$?

if [ ${retval} -eq 0 ]; then
got_good_root=1
REAL_ROOT=${i}
ROOTFSTYPE=zfs
break
fi

done;

else
got_good_root=0
fi

fi

if [ ${got_good_root} -ne 1 ]; then
prompt_user "REAL_ROOT" "root block device"
got_good_root=0
fi

continue
;;
esac

if [ "${REAL_ROOT}" = '' ]
then
# No REAL_ROOT determined/specified. Prompt user for root block device.
prompt_user "REAL_ROOT" "root block device"
got_good_root=0

# Check for a block device or /dev/nfs
elif [ -b "${REAL_ROOT}" ] || [ "${REAL_ROOT}" = "/dev/nfs" ]
then
got_good_root=1

else
bad_msg "Block device ${REAL_ROOT} is not a valid root device..."
REAL_ROOT=""
got_good_root=0
fi
done

if [ "${CDROOT}" = 1 -a "${got_good_root}" = '1' -a "${REAL_ROOT}" != "/dev/nfs" ]
then
# CD already mounted; no further checks necessary
break
elif [ "${LOOPTYPE}" = "sgimips" ]
then
# sgimips mounts the livecd root partition directly
# there is no isofs filesystem to worry about
break
else
good_msg "Mounting $REAL_ROOT as root..."

if [ "${ROOTFSTYPE}" = 'zfs' ]
then
if [ "zfs get -H -o value mountpoint ${REAL_ROOT}" = 'legacy' ]
then
MOUNT_STATE=rw
else
MOUNT_STATE=rw,zfsutil
fi
else
MOUNT_STATE=ro
fi

# Try to mount the device as ${NEW_ROOT}
if [ "${REAL_ROOT}" = '/dev/nfs' ]; then
findnfsmount
else
# If $REAL_ROOT is a symlink
# Resolve it like util-linux mount does
[ -L ${REAL_ROOT} ] && REAL_ROOT=`readlink ${REAL_ROOT}`
# mount ro so fsck doesn't barf later
if [ "${REAL_ROOTFLAGS}" = '' ]; then
good_msg "Using mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE}"
mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE} ${REAL_ROOT} ${NEW_ROOT}
else
good_msg "Using mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE},${REAL_ROOTFLAGS}"
mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE},${REAL_ROOTFLAGS} ${REAL_ROOT} ${NEW_ROOT}
fi
fi

# If mount is successful break out of the loop
# else not a good root and start over.
if [ "$?" = '0' ]
then
if [ -d ${NEW_ROOT}/dev -a -x "${NEW_ROOT}${REAL_INIT:-/sbin/init}" ] || [ "${REAL_ROOT}" = "/dev/nfs" ]
then
break
else
bad_msg "The filesystem mounted at ${REAL_ROOT} does not appear to be a valid /, try again"
got_good_root=0
REAL_ROOT=''
fi
else
bad_msg "Could not mount specified ROOT, try again"
got_good_root=0
REAL_ROOT=''
fi
fi
done
# End determine root device
...

The problem is that I need this initramfs because of the multiple PCs and Laptops. I use genkernel to build a new kernel and this initramfs automaticly.

What can I change in the bios tho hide this message? Changing the boot sequence?

My /etc/fstab

/dev/dvd0 /mnt/cdrom auto noauto,ro 0 0
UUID=a97c2681-5124-4749-baf0-dc65031460a8 / jfs noauto,noatime 0 1
UUID=00c1a898-b516-497a-9617-f10d1811eb16 none swap sw 0 0

I've also tried

/dev/dvd0 /mnt/cdrom auto noauto,ro 0 0
/dev/sdb1 / jfs noauto,noatime 0 1
/dev/sdb2 none swap sw 0 0

but it also doesn't help.

Drakeo · 10-06-2014, 05:16 PM

ok Try to explaine this again it seems the bios on that machine do not want to scan for BLKID. so in your grub make another entry just like the one you use to
boot with and title it for (this Laptop)
now were it reads root=UUID=a97c2681-5124-4749-baf0-dc65031460a8 change it to root=/dev/sd?? sda1 sdb1 etc etc. the for here is an example.

Code:

menuentry 'Slackware-14.1 GNU/Linux' --class slackware-14.1 --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-f52adeea-a45c-4dc5-b599-aecadc1709b5' {
	load_video
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='hd0,msdos1'
	if [ x$feature_platform_search_hint = xy ]; then
	  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  f52adeea-a45c-4dc5-b599-aecadc1709b5
	else
	  search --no-floppy --fs-uuid --set=root f52adeea-a45c-4dc5-b599-aecadc1709b5
	fi
	echo	'Loading Linux 3.10.17 ...'
	linux	/boot/vmlinuz-huge-3.10.17 root=UUID=f52adeea-a45c-4dc5-b599-aecadc1709b5 ro  
	echo	'Loading initial ramdisk ...'
	initrd	/boot/initrd-3.10.17.gz

change to

Code:

menuentry 'Slackware-14.1 Laptop GNU/Linux' --class slackware-14.1 --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-f52adeea-a45c-4dc5-b599-aecadc1709b5' {
	load_video
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='hd0,msdos1'
	if [ x$feature_platform_search_hint = xy ]; then
	  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  f52adeea-a45c-4dc5-b599-aecadc1709b5
	else
	  search --no-floppy --fs-uuid --set=root f52adeea-a45c-4dc5-b599-aecadc1709b5
	fi
	echo	'Loading Linux 3.10.17 ...'
	linux	/boot/vmlinuz-huge-3.10.17 root=/dev/sda1 ro  
	echo	'Loading initial ramdisk ...'
	initrd	/boot/initrd-3.10.17.gz

you can set your /etc/fstab to this

Code:

/dev/sda1        /                ext4        defaults         1   1

and grub will still find it and for machines that can scan blkid they will load it also.
now use grub entry #1 for all other machines and grub intry #2 for that laptop
let me know if it works.