10.04 Portable HD Boot Drops to BusyBox

[von Corax]

First, some background:

This semester I'm taking a course in multicore (using Cilk) and manycore (using CUDA) software development. The lab machines are 8-core systems running 10.04 with the above-mentioned tools, and I am trying to build an equivalent home system.

I've borrowed an 8-core+CUDA Windows laptop and, since this machine is not mine, I'm trying to install Ubuntu & tools on an external USB hard drive. All the instructions I found for doing this say to disconnect the internal HD first, so to avoid opening the laptop I used another machine to perform the install.

Now the problem: I can use the portable HD to boot the machine I created it with, but when I try to boot the laptop I get the message /dev/disk/by-UUID/long-string-of-hexadecimal-code does not exist and get dropped to the initramfs prompt.

I've read enough to get a vague idea of what's wrong, but I have no idea how to fix it; if anyone could walk me through I would be most grateful.

[Bashing-om]

von Corax; Hi !

Proceed in baby step (for me).
1. Can you boot up on the affected machine in "try ubuntu" mode on the install usb ?
2. Let's look at the UUID's and see if they correspond:
a) Post the output of terminal codes:

sudo blkid
sudo fdisk -l
mount

b) Now is a tedious operation. In the file manager navigate to /etc/fstab insuring that this file is on the appropriate device as depicted in the results of the above commands. Copy and paste this file to this thread. [easier in terminal, but I want to be sure that you have the correct file]
3. Depending on these results will mount the usb device's root and edit /etc/fstab file to the appropriate UUIDs ---- If UUIDs correspond already, will look and see where you installed grub to.
4. By the way, what version are you installing ?

sounds like a plan to me <== BDQ

[von Corax]

Hello, Bashing-om, and thank you for answering.

Here is the output you requested:

blkid:

/dev/loop0: TYPE="squashfs" 
/dev/sda1: LABEL="RECOVERY" UUID="9628-2FDD" TYPE="vfat" 
/dev/sda2: LABEL="OS" UUID="C27A2C0B7A2BFB35" TYPE="ntfs" 
/dev/sda5: LABEL="Data" UUID="FA922E32922DF3B3" TYPE="ntfs" 
/dev/sdb1: UUID="f68e5418-ab1e-4ba7-9f07-abfa287f361a" TYPE="ext4" 
/dev/sdb5: UUID="59f95e42-1b23-4942-abfd-d30e5abcf230" TYPE="swap"

fdisk:

Disk /dev/sda: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x2f851246

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        3264    26214400   1c  Hidden W95 FAT32 (LBA)
/dev/sda2   *        3264       37097   271764480    7  HPFS/NTFS
/dev/sda3           37097       77826   327151616    f  W95 Ext'd (LBA)
/dev/sda5           37097       77826   327150592    7  HPFS/NTFS

Disk /dev/sdb: 1000.2 GB, 1000204885504 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000347d9

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1      120874   970915840   83  Linux
/dev/sdb2          120874      121602     5843969    5  Extended
/dev/sdb5          120874      121602     5843968   82  Linux swap / Solaris

mount:

aufs on / type aufs (rw)
none on /proc type proc (rw,noexec,nosuid,nodev)
none on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /dev type devtmpfs (rw,mode=0755)
none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
/dev/sr0 on /cdrom type iso9660 (ro,noatime)
/dev/loop0 on /rofs type squashfs (ro,noatime)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
none on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev)
none on /var/run type tmpfs (rw,nosuid,mode=0755)
none on /var/lock type tmpfs (rw,noexec,nosuid,nodev)
none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ubuntu)
/dev/sdb1 on /media/f68e5418-ab1e-4ba7-9f07-abfa287f361a type ext4 (rw,nosuid,nodev,uhelper=udisks)
/dev/sda2 on /media/OS type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096,default_permissions)

/etc/fstab:

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda1 during installation
UUID=f68e5418-ab1e-4ba7-9f07-abfa287f361a /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=59f95e42-1b23-4942-abfd-d30e5abcf230 none            swap    sw              0       0
/dev/fd0        /media/floppy0  auto    rw,user,noauto,exec,utf8 0       0

On first glance, the UUIDs appear to match. Do you think changing the fstab entries to /dev/sdb1 & /dev/sdb5 would work? (I won't try it until I hear back from you.)

As to version, I'm trying to run 10.04 LTS to match the school lab machines.

Regards,
von Corax

[Bashing-om]

von Corax; So far so good. However;

You are indeed booting up on the usb drive(grub where you wanted it).//But I do not understand the /etc/fstab file// What I am looking at presently -fstab- seems to be trying to mount ubuntu's root partition on the windows partition (sda1 ???( but the uuid matches up to the usb device (sdb1)- Thus the mounting UUID is valid.

I am going to play with my system with 10.04 liveCD and see what the haps be with a good install. Back at ya soonest.

It is a learning experience <== BDQ

edit: I am back, no smarter yet.

[Bashing-om]

von Corax;

All looks good/neglecting the initial install on sda/ but:
What pops out at me is in your fstab file is an entry for a floppy drive, I bet there is no floppy drive on the system you are booting the usb drive from.

How bout commenting that line out ("#" symbol at start of line) in a text editor, save and and see if it boots up now in the affected machine.

gksudo gedit /etc/fstab

Make a backup copy first - Murphy's law applies in computers too !

sudo cp /etc/fstab /etc/fstab-bac

What results ?

[von Corax]

I may have been unclear on a few points. First, to get the above dumps I booted from the installer DVD in LiveCD mode, not from the USB drive (which is 1 TB, not 1 GB.) The sda/sdb weirdness in fstab is because all the instructions I found online on how to create a bootable external hard drive stated that one must disconnect the host machine's internal hard drives first, to prevent Grub trashing the host machine's MBR. (I discovered this after Grub had trashed my machine's MBR.)

Because the machine I want to run on is a) a laptop which b) does not belong to me, I used a different machine (an easily-openable desktop machine) to run the install. Because this machine temporarily had no internal HD, at install time the external HD was mounted at /dev/sda. I do not believe this to be the specific problem, however, as I have reconected the desktop's internal HD and am still able to boot Ubuntu from the external HD on that machine, with the external now mounted as /dev/sdb.

When I attempt to boot the laptop using the external HD, however, I eventually get a message which begins with "Gave up waiting for root device." and ends with "ALERT! /dev/disk/by-UUID/f68e5418-ab1e-4ba7-9f07-abfa287f361a does not exist." and end up at the initramfs shell prompt. This to me suggests that the machine recognizes the external as a bootable device and successfully loads Grub from the external, but that Grub then for some reason fails to find the root partition on the external. (The root volume itself can't be at fault, since it works fine on the other machine, and I don't think fstab can be the culprit if Grub can't find the volume fstab is on.)

Based on my extensive lack of experience with the Linux boot sequence I am inclined to believe I have a problem with the configuration of Grub itself, but I have no idea how to even verify my hypothesis, let alone devise a solution.

As an extra data point, executing cat /proc/cmdline returns the string

BOOT_IMAGE=/boot/vmlinuz-2.6.32-38-generic root=UUID=f68e5418-ab1e-4ba7-9f07-abfa287f361a ro quiet splash

I do appreciate the help you've provided so far, and look forward to finding a solution.

[Bashing-om]

von Corax;

Your last explains a lot....
I too am looking at the initramfs process, trying to understand why the disk will boot on one box and not another ....

reading is good, I am looking <== BDQ

[Bashing-om]

von Corax;

Here's a thought; initramfs is presently configured for the devices on the install machine, when attempting to boot up from the lap top, those devices are not present.
Good tutorial on the initramfs process:
http://www.dedoimedo.com/computers/u...nitrd-bug.html

So, what happens when the initramfs is updated ?

sudo update-initramfs -u

Otherwise. might consider it as a failure to map to device situation.

hth <BDQ

[von Corax]

That looks promising. I'll try it this evening.

(I had actually seen the page you linked before I ran into trouble, when I was looking for instructions for this non-standard install; later, when I needed it, I couldn't remember the Google query I had used. )

EDIT: That definitely appears to be the problem, but I can't use their solution of restoring the previous version of initrd.img because I don't have a previous version of initrd.img. Any suggestions?

[von Corax]

von Corax;
So, what happens when the initramfs is updated ?

sudo update-initramfs -u

Otherwise. might consider it as a failure to map to device situation.

I can only boot the laptop from CD, and update-initramfs refuses to run when booted from read-only media; I ran update-initramfs on the desktop, but I still can't boot the laptop.