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Thread: Quad Boot OS with separate boot partition

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  1. #1
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    Quad Boot OS with separate boot partition

    Hi, So out of bordom I thought I'd see how to take advantage of having a separate /boot partition using an old laptop for experimentations. I know many will say don't bother but please, let's accept I want one.
    Set up so far:



    Whilst I have allocated some partitions for other Linux OS's they're not all installed yet. I tried to install Lubuntu but messed up somewhere to do with how to deal with /boot during install. Lubuntu grub wouldn't see Ubuntu. Recreated /boot using a backup image and now boot into Ubuntu but now grub can't see Lubuntu.

    So, question: When I install other OS's, what is the proper way of dealing with the /boot partition? SHould I always mark it as /boot and format it with each install (I did this before and caused errors)?

    Sorry for being so long-winded.

    Thanks in advance.
    Last edited by Mr_JMM; November 13th, 2012 at 06:50 PM. Reason: image, spelling
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  2. #2
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    Re: Quad Boot OS with separate boot partition

    Bump.

    Additional: Each time I install a new distro it replaces grub. All other distro's are missing from the grub menu and all attempts to update grub fail.
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  3. #3
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    Re: Quad Boot OS with separate boot partition

    So it appears that each installation is replacing all the files in /boot with it's own.
    Thus os-prober is unable to find any other /boot files for other installations.

    I presume that the use of a universal /boot directory is not possible for a multiboot system.
    I do not know for sure but it seems logical.
    There may be other ways to configure this but by default each install would write its own files to /boot.

    I know; not much help.
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  4. #4
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    Re: Quad Boot OS with separate boot partition

    Odd as from what I've read, a shared boot is ideal when there's multiple distros. I'm guessing there is something I am doing wrong when I install each distro - marking the boot partition and formatting it.

    So I guess what I need to know is: Now that I've installed all four OS's, how do I get grub to see the two missing Linux distros? All it see are the newest Linux and Windows Vista.
    Updating grub via a live CD doesn't work, in that it never picks up the other distros.

    Alternatively, I'd like to know how I should install the three linux distros (if I delete them and start again) so that the /boot partition idea works as expected.

    Many thanks.
    Last edited by Mr_JMM; November 14th, 2012 at 05:46 PM.
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  5. #5
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    Re: Quad Boot OS with separate boot partition

    I have seen that too but there seems to be issues:
    http://www.googlubuntu.com/results/?...lubuntu.com%2F

    Edit:
    If you are formatting the /boot part. on each install, then there are no files related to the previous installs for os-prober to find.
    I would think the other installs would be unbootable without their /boot files. there must be a way as I too have seen this advised, but I don't know as I have never tried.
    Last edited by arpanaut; November 14th, 2012 at 06:01 PM. Reason: added after link.
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  6. #6
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    Re: Quad Boot OS with separate boot partition

    Thanks for that link. Seems that grub2 may not play nicely with a separate boot.
    Also, I see your point about overwriting boot each time. I just figured that grub would find the other distros just as it would if each distro had it's own boot file.

    Unless anyone can correct me on the above thoughts I guess I'll either have to learn to edit grub custom files or remove the separate boot. Or go back to grub 1... Dang.
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  7. #7
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    Re: Quad Boot OS with separate boot partition

    I have never seen anyone say a shared /boot should work. And several that have posted who tried all failed. The only place now that you do have a shared boot is with UEFI, but that is totally different.

    You can have a shared grub partition, but that does not have any system kernel files, just grub. That worked better with grub legacy as you could install grub to a PBR - partition boot sector and chain load each install. I used that with grub legacy and at first did not like grub2 as chain loading did not really work with grub2.

    But with grub2 you can have the one install you primarily boot in charge and with a sudo update-grub add in all the other installs. But updates in each install required updates to main install also. Often better to manage other installs yourself and manually edit grub2's 40_custom and turn off os-prober.

    How to: Create a Customized GRUB2 Screen that is Maintenance Free.- Cavsfan
    https://help.ubuntu.com/community/Ma...tomGrub2Screen
    For info on UEFI boot install & repair - Updated Mar 2015:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  8. #8
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    Re: Quad Boot OS with separate boot partition

    Cool idea, I am working on a similar configuration on my home machine, five partitions on a 1 TB disk, five operating systems.

    If you are using a common /boot partition among different distro installations, you definitely do not want to reformat it with each install. If you do so, then all previously installed kernel files will be gone.

    A problem I can see in trying to implement your scheme is that each distro does not identify these kernel files (vmlinuz, initrd, System.map) uniquely. Note the following naming:
    Code:
    RHEL:
    config-2.6.18-308.16.1.el5
    initrd-2.6.18-308.16.1.el5.img
    symvers-2.6.18-308.16.1.el5.gz
    System.map-2.6.18-308.16.1.el5
    vmlinuz-2.6.18-308.16.1.el5
    
    Mint:
    abi-3.2.0-23-generic
    config-3.2.0-23-generic
    initrd.img-3.2.0-23-generic
    System.map-3.2.0-23-generic
    vmlinuz-3.2.0-23-generic
    
    Debian:
    config-2.6.32-5-amd64
    initrd.img-2.6.32-5-amd64
    System.map-2.6.32-5-amd64
    vmlinuz-2.6.32-5-amd64
    There is no guarantee that you will not run into naming conflicts between distributions. Analyzing the contents of /boot would be quite a task. Organizing using a directory heirarchy would be the way I would go, but then you are looking at manually maintaining each entry in grub.cfg so that it refers to the correct sub-directory for each distro. But, this would break aptitude (Update Manager for you GUI people) updates to the kernel.

    It would seem that each distro assumes that it has exclusive control over /boot.

    I admire the idea of having a shared /boot, it is do-able with some effort, though it may be easier to make sure you have a shared grub configuration instead.

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