How to boot from raid device? - Mandriva

This is a discussion on How to boot from raid device? - Mandriva ; Hi, I seem to be caught in catch22 ;>). I set up a 2 disk raid 1 system. So far, so good. The problem is, I can't boot from it. It works fine if I boot from a third hard ...

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Thread: How to boot from raid device?

  1. How to boot from raid device?

    Hi,

    I seem to be caught in catch22 ;>).

    I set up a 2 disk raid 1 system. So far, so good.

    The problem is, I can't boot from it. It works fine if I boot from a
    third hard disk.

    I guess it's not surprising since mdadm can't run before the raid array
    is mounted and that doesn't happen.

    Also, I used mdadm to create the array; and I don't see anything in mdadm
    about setting up a superblock. It says it checks to see if there is a
    superblock but doesn't say how to create one (or am I overlooking it?)

    Do I have to use raid tools first to create the array with a superblock?
    If I do that will I lose the data that's already installed on the array?

    The solution must have something to do with the boot loader. I'm using
    grub but I set it up in the boot sector; not in a separate boot
    partition.

    I can't find anything on how to do this. Any help, or a nudge in the
    right direction, would be greatly appreciated.

    Thanks,


    Frank



  2. Re: How to boot from raid device?

    Hi, I forgot to mention that I'm using LM2008.0 and the two drives are
    sata.


    Frank


  3. Re: How to boot from raid device?

    On Sun, 03 Feb 2008 17:12:19 -0500, Frank Dreyfus wrote:

    > I set up a 2 disk raid 1 system. So far, so good.
    > The problem is, I can't boot from it. It works fine if I boot from a
    > third hard disk.


    lilo can boot from a raid 1 system. Read /usr/share/doc/lilo/README.raid1.bz2

    Regards, Dave Hodgins

    --
    Change nomail.afraid.org to ody.ca to reply by email.
    (nomail.afraid.org has been set up specifically for
    use in usenet. Feel free to use it yourself.)

  4. Re: How to boot from raid device?

    on Monday 04 February 2008 10:03
    in the Usenet newsgroup alt.os.linux.mandriva
    David W. Hodgins wrote:

    > On Sun, 03 Feb 2008 17:12:19 -0500, Frank Dreyfus
    > wrote:
    >
    >> I set up a 2 disk raid 1 system. So far, so good.
    >> The problem is, I can't boot from it. It works fine if I boot from a
    >> third hard disk.

    >
    > lilo can boot from a raid 1 system. Read
    > /usr/share/doc/lilo/README.raid1.bz2


    Can I add that there are newer versions of Lilo that claim handle
    raid better. Also think about having a /parallel/ raid-1 system
    (read David's reference) and think about having a separate non-raid
    partition for /boot.


    --
    sig goes here...
    Peter D.

  5. Re: How to boot from raid device?

    "Peter D." wrote in news:uf7j75-74e.ln1
    @psd.motzarella.org:

    Hi Peter,

    > Can I add that there are newer versions of Lilo that claim handle
    > raid better.

    I have 24.6.1 which is pretty close to the latest. I don't think I want
    to take my chances with a newer version at this point. I don't think
    cooker has a later version yet.

    > Also think about having a /parallel/ raid-1 system
    > (read David's reference)

    Yes, my system is fully parallel; at least for sda1 and sdb1 and that's
    what I'm trying to boot from.

    > and think about having a separate non-raid
    > partition for /boot.

    I may have to try that as a last resort. It would mean reformatting and
    going back to square one so I think I'll putter with this for a bit
    longer.

    Thanks for your help,


    Frank


  6. Re: How to boot from raid device?

    on Tuesday 05 February 2008 06:22
    in the Usenet newsgroup alt.os.linux.mandriva
    Frank Dreyfus wrote:

    > "Peter D." wrote in news:uf7j75-74e.ln1
    > @psd.motzarella.org:
    >
    > Hi Peter,
    >
    >> Can I add that there are newer versions of Lilo that claim handle
    >> raid better.

    > I have 24.6.1 which is pretty close to the latest.


    I've only got 22.6.1 with Mandriva 2008.0. ;-)

    Look at
    and decide if there is anything of value to you.

    > I don't think I want
    > to take my chances with a newer version at this point.

    [snip]

    OK


    --
    sig goes here...
    Peter D.

  7. Re: How to boot from raid device?

    Frank Dreyfus wrote:

    > Hi,
    >
    > I seem to be caught in catch22 ;>).
    >
    > I set up a 2 disk raid 1 system. So far, so good.
    >
    > The problem is, I can't boot from it. It works fine if I boot from a
    > third hard disk.
    >
    > I guess it's not surprising since mdadm can't run before the raid array
    > is mounted and that doesn't happen.
    >
    > Also, I used mdadm to create the array; and I don't see anything in mdadm
    > about setting up a superblock. It says it checks to see if there is a
    > superblock but doesn't say how to create one (or am I overlooking it?)
    >
    > Do I have to use raid tools first to create the array with a superblock?
    > If I do that will I lose the data that's already installed on the array?
    >
    > The solution must have something to do with the boot loader. I'm using
    > grub but I set it up in the boot sector; not in a separate boot
    > partition.
    >

    I still have lilo as bootloader, because it's well documented for raid1.
    My lilo.conf starts that way:

    # File generated by DrakX/drakboot
    # WARNING: do not forget to run lilo after modifying this file

    default="tmbcustom_2.6.23.9-2"
    boot=/dev/md0
    map=/boot/map
    install=menu
    keytable=/boot/de-latin1-nodeadkeys.klt
    raid-extra-boot=mbr

    The key is the last line. It writes the mbr of _both_ disks everytime lilo
    is run. That way, it is still possible to boot even if one drive is
    missing.
    --
    vista policy violation: Microsoft optical mouse found penguin patterns
    on mousepad. Partition scan in progress to remove offending
    incompatible products. Reactivate MS software.
    Linux 2.6.23.9-2mdvtmbcustom. [LinuxCounter#295241,ICQ#4918962]

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