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Thread: GPT+BIOS on openSUSE 13.1 x64

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    Default GPT+BIOS on openSUSE 13.1 x64

    What is the best way to set up a GPT disk with a traditional BIOS on openSUSE 13.1 x64? I Googled it and found that a protective MBR is one answer, or creating a separate small boot partition to put Grub2 on. I see very little info on GPT+BIOS, and almost none pertaining to openSUSE. In the YaST setup phase, I don't see anything that lets you set a partition on a disk to GPT besides a toggle option in the last screen to create a MBR or not on one partition. Is there an option hiding somewhere? I know YaST detects whether or not you're booting the CD from a BIOS or UEFI computer, but does the installer let you create GPT partitions with YaST when booting from the non-LILO DVD?

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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    Quote Originally Posted by pirithous View Post
    What is the best way to set up a GPT disk with a traditional BIOS on openSUSE 13.1 x64?
    I've done this on an external drive. It works fine with linux. It might be a problem with Windows.

    The protective MBR is a standard part of GPT.

    My advice: Create a "BIOS Boot Partition". You can position this between sector 34 and 2047, a part of the disk that won't otherwise be used.

    If you are starting with a clean (unpartitioned) disk, then use "gdisk", and use "x" to get to expert mode. Then set the alignment to 1. Otherwise you will have problems creating a partition starting at sector 34.

    Create a new partition at 34, ending at 2047. Give it the partition type code of "ef02".

    Then write the changes and exit "gdisk". Best to restart "gdisk" with the standard alignment, before doing anything else.

    When you are satisfied with the partitioning, just install. Tell the installer to put grub2 in the MBR. That works fine, in my experience. The grub-installer will recognize that this is a GPT disk, and will automatically put part of its code in the BIOS Boot Partition.

    You will need to install booting to the MBR. The standard generic MBR boot code does not understand GPT, so won't find any partitions to boot. But Grub2 does that nicely.

    An alternative, which I have not tested, is to setup hybrid partitioning. You can also do that with "gdisk", though all of the advice I have seen recommends not doing this. With hybrid partitioning, you can have up to 3 partitions that are listed in both the MBR and the GPT partition table. As long as you are booting one of those, the generic MBR boot code should be able to boot a hybrid partition.
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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    It looks like gdisk isn't loaded when choosing "Rescue Mode" using the DVD, although fdisk is. I would rather not pull the drive out of this PC. What are my options?

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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    Quote Originally Posted by pirithous View Post
    It looks like gdisk isn't loaded when choosing "Rescue Mode" using the DVD, although fdisk is. I would rather not pull the drive out of this PC. What are my options?
    Hi
    Download and burn the openSUSE Rescue system to a usb device and use that.
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    please show your appreciation and click on the star below... Thanks!

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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    I got the Rescue system working from a USB drive, but had some questions. Am I only supposed to create the BIOS Boot partition in gdisk, then set up the others through YaST? I tried that, and after the install I ran: "gdisk /dev/sda", and it says it found a valid GPT. However, when running: "gdisk /dev/sda2" and "gdisk /dev/sda3" (the two data partitions), it found no GPT, or said it was invalid. I also tried another install, and used gdisk beforehand to set up the partitions to import into YaST, but YaST doubled everything and didn't want to import the partition setup. Thanks for the help.

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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    Quote Originally Posted by pirithous View Post
    Am I only supposed to create the BIOS Boot partition in gdisk, then set up the others through YaST? I tried that, and after the install I ran: "gdisk /dev/sda", and it says it found a valid GPT.
    I don't have an answer for that. It is possible that Yast notices that this is a traditional BIOS system, and erase the GP table.

    I always do full partitioning with "gdisk" (or "fdisk" in the non-GPT case), and then during an install, I go to expert mode and just tell the installer which of the existing partitions to use for what.

    In the case of the external disk using GPT, I actually first installed with it plugged into a UEFI system. I then later converted to using "grub2" and a BIOS boot partition, so that I could boot it on an older BIOS system.
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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    After partitioning with gdisk, YaST says it cannot find mount points. I can create a new GPT in YaST, but then it erases the BIOS Boot partition I created in gdisk. Do you have any other suggestions?

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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    Quote Originally Posted by pirithous View Post
    After partitioning with gdisk, YaST says it cannot find mount points. I can create a new GPT in YaST, but then it erases the BIOS Boot partition I created in gdisk. Do you have any other suggestions?
    Are you installing from the DVD?

    I can try a fresh install to my external drive, to see whether I get the same thing. I'll start by erasing the current partitioning and create a new setup.
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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    Quote Originally Posted by nrickert View Post
    Are you installing from the DVD?

    I can try a fresh install to my external drive, to see whether I get the same thing. I'll start by erasing the current partitioning and create a new setup.
    Yes, I am installing from the DVD. It looks like gdisk will let you set the sector alignment and partition the disk all in one try, without exiting. I think I tried exiting and then going back into it and it didn't matter. If you want to try and see what happens, I'm curious to see what result you get. YaST doesn't tell the user which partition is GPT or MBR (unless I'm not seeing something)...maybe that would be a nice feature to make things less confusing.

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    Default Re: GPT+BIOS on openSUSE 13.1 x64

    Quote Originally Posted by pirithous View Post
    Yes, I am installing from the DVD.
    Okay, it is busy installing as I write this.

    I probably did not give enough detail before.

    I first partitioned the disk with "gdisk"
    Code:
    GPT fdisk (gdisk) version 0.8.7
    
    Partition table scan:
      MBR: protective
      BSD: not present
      APM: not present
      GPT: present
    
    Found valid GPT with protective MBR; using GPT.
    Disk /dev/sdf: 156301488 sectors, 74.5 GiB
    Logical sector size: 512 bytes
    Disk identifier (GUID): 11B54440-F03F-49E9-84D6-9ADA51D8B3F2
    Partition table holds up to 128 entries
    First usable sector is 34, last usable sector is 156301454
    Partitions will be aligned on 2-sector boundaries
    Total free space is 0 sectors (0 bytes)
    
    Number  Start (sector)    End (sector)  Size       Code  Name
       1              34            2047   1007.0 KiB  EF02  BIOS boot partition
       2            2048        41945087   20.0 GiB    8300  Linux filesystem
       3        41945088        62916607   10.0 GiB    8200  Linux swap
       4        62916608       156301454   44.5 GiB    8300  Linux filesystem
    That's the output from "gdisk -l". The disk itself is an old IDE disk mounted in an external enclosure. It's a left-over from a long discarded older computer.

    Next, the install to that external drive.

    I'll skip the preliminaries, and get to the partitioning section.

    On the first partitioning screen, I clicked "Create Partition Setup"

    On the next screen, I ignored the check boxes. Instead, I clicked "Custom Partitioning". That's what allows me to use existing partitions.

    The next screen presented a list of partitions. In my case, this was complex because it had partitions for the internal drive, the external drive, and the USB flash drive that I had used with the DVD iso image.

    I looked for the partitions that I had created on the external drive. I ignored the BIOS boot partition there, as it's use should be automatic by grub install. So I started with "/dev/sdf2" for the root partition. I right clicked on that, and selected EDIT.

    Next, on the edit page, I checked the box "Format Partition". I set the file system to "ext4". I checked the box "Mount Partition", and I set the mount point to "/".
    I did about the same for "/dev/sdf4", except that I set the mount point to "/home".
    For the swap partition, I set the file system to "swap" and the mount point to "swap", and also checked the boxes to format partition and mount partition.

    When I accepted the result, there was a strange message "Your boot partition is smaller than 12MB". I think that is a spurious message, and I went ahead and ignored it.

    In the meantime, install has completed and the newly installed system is up and running (I only install XFCE).

    I hope that helps. My best guess is that you missed the part about setting a mount point.
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