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Thread: dual boot on 2 drives?

  1. #1
    Join Date
    Sep 2007
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    997

    Default dual boot on 2 drives?

    I have my desktop back but I need to reconfigure the whole thing.

    My Windows partitions are full (computer was loaned!) and my Linux operating systems were not updated.

    I was going to re-install and have a new setup.

    The plan is to have larger partitions anyway and use VirtualBox on the Linux OS/partition.

    I'm hoping to obtain some suggestions and advice on how to proceed.

    It's not crucial which distro you prefer but that you don't mind suggesting an approach!

    It might be convenient if you also use Windows though even if rarely so you might have some interest in this topic!

    I have two hard drives: 320GB and 500GB. I was going to use the 500GB for XP Pro since this drive is a bit older but both are SATA.

    The 320GB drive is what I was using, though. I'm open to suggestions, however. I have Windows on the 320GB HDD but the Windows partitions are around 25GB each and full. I was going to resize all the partitions including the Linux ones (they are about 5 of 20GB each). There's about 100GB of unallocated space.

    I thought the idea of booting Linux on one drive is good and Windows on the other drive. I would have Windows on both drives just for BIOS updates or whatever but the 'Linux' drive would have the smaller Windows partition (mostly unused). Or if there's a better idea, please share!

    I am not sure how to set this up, though, as I've never done it. All my configurations have been having Linux and Windows on the same drive. I read that Grub2 can easily configure two drives for booting but how?

    I read this in the forum after a search:
    f you use multiple drives and switch them in the BIOS, you don't have to worry about sharing drives.

    You really want an OS to have its own disk. If you share two OS's on one disk, one of them will end up on the inner tracks and will run much more slowly.

    Instead of switching in the BIOS, you can put each OS on its own drive and use GRUB to choose. If you are very clever, you can add a small script to each OS that modifies the default GRUB setting, so you can make a "shutdown and reboot as the other OS" button if you want.
    I'm still confused about having both drives having a bootable option. My 500GB drive is viewable but I can't boot it unless I disconnect the 320GB drive.

    The 500GB drive is a previously configured system with Windows and Linux but since it's been untouched for a while, I figure I'd check to see if there's any data I want and then dedicate it to either Windows or Linux.

    Can anyone advise for this project? I was going to dual boot on the one drive and then move the other drive to another build but for now, I thought I would have one computer boot the two drives (I need a cpu before I complete the other build).

    Thanks in advance for any suggestions/advice. I hope having this setup is better than multi-booting on one drive: I find it a bit irritating when you want to resize partitions and it seems logical to have Windows on its own drive and vice versa for Linux (dedicated drive for Linux). Right????

  2. #2
    Join Date
    Sep 2007
    Posts
    997

    Default

    SIXTY VIEWS AND NOT EVEN A COMMENT OF 'HAHA, THAT'S EASY...GOOD LUCK BORKING YOUR DRIVES, DUDE?!" C'mon, it's almost Xmas time... I invite any comments.

    I am looking into one drive booting Windoze and one booting Linux. I just haven't configured this way before so wasn't sure the best path to take.

    I believe a Windows drive is set up first and then install Linux on the other drive and sometimes Grub will pick them both up. Gotta read a bit more on it, though, since I'll probably use Grub2 instead of Grub Legacy.

    I believe I can also control the booting via the BIOS but it's a bit more of a pain although I think there's an advantage for having separate file systems.

    Or maybe this is not a good idea since you're only using one drive all the time... whereas dual-booting one one drive means it's in use constantly... that was the negative argument I just read.

    Okay, 'done writing to myself.... 'strange that some ppl thought the title sounded interesting enough to warrant a view!

  3. #3
    Join Date
    Aug 2007
    Posts
    6,633

    Default

    Basically grub2 is all you want. The current code automatically allows booting from any hd for Win XP with automated mapping (i tested that map command even 1 mounth before it was officially in grub2). You bascially install your XP with 1 hd attached, then you configure it as 2nd hd and use the first one for linux. When you run update-grub it will find every other os (if not feel free to patch os-prober). Win is no problem to boot from 2nd or 3rd devices - works fully automatic.

  4. #4
    Join Date
    Apr 2008
    Posts
    325

    Default

    What I would suggest is putting windows on the first drive (sda) and putting linux on the second (sdb). Windows can be a little weird if it thinks it's not on the primary drive, so it is easier to let it have it's way.

    Apart from that, this should be completely routine with any halfway competent bootloader (e.g. Grub, Lilo, Grub2...)

  5. #5
    Join Date
    Aug 2007
    Posts
    6,633

    Default

    No i would put it the way i explained before. grub2 will manage all for you. The map command is used to virtually switch the drives. You find the relevant code in /etc/grub.d/30_os-prober - no need to put linux hd as 2nd, use xp only for install as single drive - much better, does not change the mbr, drive will still work fully without 2nd one.
    Code:
      case ${BOOT} in
        chain)
    
          cat << EOF
    menuentry "${LONGNAME} (on ${DEVICE})" {
    EOF
          prepare_grub_to_access_device ${DEVICE} | sed -e "s/^/\t/"
    
          case ${LONGNAME} in
            Windows\ Vista*|Windows\ 7*)
            ;;
            *)
              cat << EOF
            drivemap -s (hd0) \${root}
    EOF
            ;;
          esac
    
          cat <<EOF
            chainloader +1
    }
    EOF
        ;;

  6. #6
    Join Date
    Sep 2007
    Posts
    997

    Default

    Quote Originally Posted by Kano View Post
    No i would put it the way i explained before. grub2 will manage all for you. The map command is used to virtually switch the drives. You find the relevant code in /etc/grub.d/30_os-prober - no need to put linux hd as 2nd, use xp only for install as single drive - much better, does not change the mbr, drive will still work fully without 2nd one.
    Thanks, Kano!
    I think I understand the concept and process! At least, I hope I do.

    1)Install Windows first on the drive as usual and after it's complete, connect the other drive but setup in BIOS so that it's the one to boot up first. When you use the Linux install CD/DVD, it will detect it as 'FIRST' HDD and then it will be labelled sda and the Windows drive will become sdb. Grub2 will detect the Windows drive and it does the mapping automatically? Or?

    2)When booting up the computer from a cold boot, the Grub screen should come up and allow a choice of the Windows drive or the 'Linux drive.' Even if I disconnect the Windows drive (for theory purposes), the Linux drive will boot up as normal allowing either choice (but, selecting the Windows drive will probably boot up a blank screen).

    3) This allows a smooth bootup without needing to switch the BIOS boot options.

    Well, I guess I still have some confusion, mostly how Grub2 manages to write to the MBR (of the Linux drive?) and still detects the Windows drive. I suspect it just scans all drives and partitions and 'finds' the Window drive?

    I had one more topic to add, however. I might be able to get Windows 7 so this configuration might be a slight change from XP/Linux to Windows 7/Linux. I suppose the process is the same, though, although I am sure the Windows 7 bootloader works much more differently than XP's.

    One last question is whether this setup is recommended. I just thought this setup might work a bit more efficiently and allows less partitioning or headache. However, it means there's always one drive NOT writing/reading. Is that okay? Isn't it still on? The options are:

    1) two HDDs - 320GB: Windows 7; 500GB: Linux - one drive is running and accessed, the other is not being accessed

    2) ONE LARGE HDD - 500GB +: Windows 7 / Linux Dual Boot - traditional/typical dual boot configuration - there might be more happening,though

    Only certain areas of the disk is accessed at different times although ntfs-3g allows accessing Windows partitions while in Linux

    I don't know which configuration is preferable or whether it matters.

    One advantage of the typical dual boot is that I can use the other HDD towards another build! But, the separate drives booting up the respective operating systems allows for way more space per OS.

    Comments? I think if I can get some good feedback, I will decide on one of the approaches and not bore readers much longer.

    Thanks again, Kano, helpful as always!

    Robbie, I read of that idea before, of using the Windows HDD as 1st HDD but my experience of the separate HDDs w/ their separate OS is not one I'm familiar with let alone knowing what is needed using Grub2.

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