Grub 2 Basics

[ir926]

My lab just purchased a new Mac Pro and we would like to be able to dual boot OS X and Ubuntu 10.04. Instead of installing the the OSs side by side on a single hard drive (which worked just fine for my personal laptop running Vista and Ubuntu), I have been asked to have one hard drive run OS X and a second internal drive run Ubuntu.

So - I created a LiveCd, ran it, and got to the section asking where I want to put Ubuntu. I selected the second, newly installed hard drive (which had nothing at all on it) from the drop down menu, and the text above changed to something like "There are no operating systems installed on this computer". Although I didn't think it was an issue at the time, I now fear this is a major part of my problem. I checked the Advanced settings, and saw that the boot loader was being installed to sda, the first hard drive, which I had no problems with. I installed Ubuntu and got the happy prompt saying the install was successfull. I restart, remove the disk, etc. and... No GRUB2 menu on reboot, just a straight jump to the Apple login screen.

I thought that maybe because GRUB2 default is to skip the menu if no second OS is found, that having GRUB2 and OS X on sda while Ubuntu is only on sdb might cause GRUB2 not to recognize the existence of Ubuntu, but I have been unable to force the menu to appear to even see if Ubuntu is an option on the menu. A few places have indicated to me that restarting while holding Shift would do the trick - it doesn't seem to.


Here's to hoping someone knows what I'm doing wrong... Thanks!

[ranch hand]

ir926

When you boot to the Mac OS (I know know nothing about them) can you see the files for Ubuntu?

If you boot to the Live CD can you see both of the OS' and their files?

I do know that there are people dual booting Mac and Ubuntu. I am not sure what the menu entry looks like, don't think I have seen one.

It does seem like grub should detect it.

If you want the grub menu to show use the Live CD and edit the /etc/default/grub file so that it looks like this;

 GRUB_DEFAULT=0
#GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT="10"
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

While there you can take a look at the /boot/grub/grub.cfg file and see if Mac is on there.

I find it a little hard to believe that grub is installed to the MBR of the first drive, sda I assume. It it was a grub menu from Ubuntu coming up I would expect to be booting to Ubuntu automatically. Also the default should be to show a menu as you have another OS on there. Third you say that the message was that there was no other OS on the box.

I think that you should make sure both OS' look OK. Make sure you know how to get the Mac bootloader back on the MBR. Follow these instructions;

https://wiki.ubuntu.com/Grub2#Recove...20via%20LiveCD

to get grub on the MBR, ignoring the part about editing files. What you need is grub on the MBR of sda and, assuming you can then boot to Ubuntu, run from there;

sudo update-grub

this should, if it is not there, get the Mac menu entry on to your grub installation.

[ir926]

ranch hand

Thanks for getting back to me. Sadly I can only access the Mac when I'm in the lab and I had the misfortune of posting my question the day before they closed the place for some IT security work, but now we're back in business.

I tried to run Ubuntu from the LiveCD and every little step was taking forever and a day. Is this because I burned the disk too fast and made it less "bootable"? I did manage to take a look at grub.cfg and OS X is there. I guess this means I didn't install grub to sda as I thought...

Before I try to install grub to sda I'm going to try to burn a new cd at a lower burn rate and hopefully I can have things work a little faster. I'll post again when I've tried to install grub.

[ranch hand]

The live CD runs pretty slow, particularly booting up. You are working from the CD not a hard drive. It is slow. It does speed up some as more and more stuff gets onto the ram (if you have enough ram).

If you have an external and install on it you can work from it faster. The CD is safer as you will not be interfering with grub in any way.

It is good to hear that the Mac install is on the grub.cfg file. Did it look right? That would be my concern. If it is right and you know how to fix the Mac bootloader back onto the MBR, then I would put grub on there and find out if it works.

Have FUN.

[ir926]

ranch hand

You were right about it starting to run faster as more gets on the RAM.

I'm not sure how to apply the instructions from the link you sent me to to this system... In particular, I am asked to remember which device is my Linux distribution - is that sdb2? Also, there is mention of /boot on a separate partition that needs to be mounted "if you have one". Do I need to worry about this?

ubuntu@ubuntu:/etc/default$ sudo fdisk -l

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sda: 1000.2 GB, 1000204886016 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: 0x000052ff

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1      121602   976762583+  ee  GPT

WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sdb: 1000.2 GB, 1000204886016 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: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1           1        2047+  ee  GPT
/dev/sdb2   *           1      116680   937224192   83  Linux
/dev/sdb3          116680      121602    39535616   82  Linux swap / Solaris

[kepps03]

Is there a way to delete Grub 2 and use only Windows 7/Vista loader on a multi boot system? I like windows boot loader leaps and bounds more and I would love to be able to use it without grub 2. I delete it b4, but was unable to load Ubuntu without it. Is it even possible to delete grub 2 and use windows boot loader to load Ubuntu.


-My version is Ubuntu 10.04


Please keep your replies nice. I'm new to Ubuntu and I don't know where to start. Yes! A noob! So please respect me and I'll do the same.

[ranch hand]

Is there a way to delete Grub 2 and use only Windows 7/Vista loader on a multi boot system? I like windows boot loader leaps and bounds more and I would love to be able to use it without grub 2. I delete it b4, but was unable to load Ubuntu without it. Is it even possible to delete grub 2 and use windows boot loader to load Ubuntu.


-My version is Ubuntu 10.04


Please keep your replies nice. I'm new to Ubuntu and I don't know where to start. Yes! A noob! So please respect me and I'll do the same.

This is a thread about grub2. You would probably get getter support in the Absolute Beginners Talk portion of the forums.

[ranch hand]

ranch hand

You were right about it starting to run faster as more gets on the RAM.

I'm not sure how to apply the instructions from the link you sent me to to this system... In particular, I am asked to remember which device is my Linux distribution - is that sdb2? Also, there is mention of /boot on a separate partition that needs to be mounted "if you have one". Do I need to worry about this?

ubuntu@ubuntu:/etc/default$ sudo fdisk -l

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sda: 1000.2 GB, 1000204886016 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: 0x000052ff

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1      121602   976762583+  ee  GPT

WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sdb: 1000.2 GB, 1000204886016 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: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1           1        2047+  ee  GPT
/dev/sdb2   *           1      116680   937224192   83  Linux
/dev/sdb3          116680      121602    39535616   82  Linux swap / Solaris

You have installed on one partition. I would have used 2 (/ and /home0 to make any future recovery easier.

Some folks use a /boot partition too. I do not think this is a good thing.

Because you did not do that you do not need to worry about it.

I do not know what this GPT bussiness on sdb is either but since you want to install grub on sda I do not think this should be a problem.

All you need to worry about, seeing you already checked your grub files, is the 2 commands;
update-grub
and
grub-install /dev/sda

This will update grub again, probably not needed and install grub on the MBR of sda.

GPT bothers me so I looked it up;

http://www.search.com/reference/GUID_Partition_Table

I guess it is nothing to worry about, just something new to learn about.

[ir926]

As I was trying to put grub on sda, I kept getting odd requests. When I went to update-grub, I was told no device was mounted. When I went to mount a device, I was told I needed to specify a filesystem type.

I decided to go a slightly less elegant, but perhaps simpler route. I opened the case, swapped the hard drives, and restarted...

For some reason, the Mac still jumps to OS X. However, I can force a manual selection by holding down the "Option" key during restart. This gives me an option between Mac and Windows.

Yes, Windows - which, when clicked, actually turns out to be Ubuntu, and grub opens up beautifully, recognizing Ubuntu and OS X. Equally importantly, it also recognizes that Ubuntu is on sda and OS X is on sdb. Oddly (or perhaps not, since grub is a way better piece of work than the Mac loader) I can then load OS X from grub with no difficulty.

Do you know if there is a way for me to make sure grub is the default selection without my having to go through the really rather aweful Mac interface?

[ir926]

I guess I should add that now I can - even if I have to jump through a few hoops - run Ubuntu without the livecd, if that makes any steps easier...