partition based raid1 and multi boot Ubuntu/Xubuntu

partition based raid1 and multi boot Ubuntu/Xubuntu

[Gavin Whitehead]

I'm not sure if this is a GRUB2 problem or a RAID/MD issue but here goes...

I want to set up a machine that will boot two Linux installations using 
raid 1 partitions and Windows XP on a single partition.

I have two identical disks partitioned as follows

$ cat /proc/partitions
major minor  #blocks  name

    8        0  244198584 sda
    8        1   30720000 sda1
    8        2   30720000 sda2
    8        3   40960000 sda3
    8        4          1 sda4
    8        5    4194304 sda5
    8        6  137601024 sda6
    8       16  244198584 sdb
    8       17   30720000 sdb1
    8       18   30720000 sdb2
    8       19   40960000 sdb3
    8       20          1 sdb4
    8       21    4194304 sdb5
    8       22  137601024 sdb6

I installed WinXP first in sda3.

I then installed Ubuntu 11.04 from the Alternate CD and created some 
raid1 devices
     md0        sda1 sdb1    /
     md1        sda5 sdb5    swap
     md2        sda6 sdb6    /home

I set the boot flag on sda1 and sdb1.
This worked a treat.  I could boot in to either Ubuntu 11.04 to WinXP.  
I tested the RAID1 (power down, unplug a disk, power up, power down, 
replug the disk, power up,  use 'mdadm --add' to rebuild the array).  
Brilliant.

Then I installed Xubuntu 11.10 from the Alternate CD.  For this install 
I created one new raid1 device (md3) and reused md1 and md2
     md3        sda2 sdb2    /
     md1        sda5 sdb5    swap
     md2        sda6 sdb6    /home

I set the boot flag on sda2 and sdb2.

After the install had completed and grub2 had built the grub.cfg I only 
had my new Xubuntu 11.10 in the boot menu.  The Xubuntu 11.10 install 
works perfectly (and I can boot in to Win XP) but I can't boot in to the 
Ubuntu 11.04 installation.  I've re-run 'update-grub' but it doesn't 
find the other installation.

If I run 'sudo mount /dev/md0 /mnt' I can access the Ubuntu 11.04 files.

Is my intended configuration (tri-boot with two raid1, partition based, 
Linux installations and XP on a single parition) unachievable?

Gav

Re: partition based raid1 and multi boot Ubuntu/Xubuntu

[NeilBrown]

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On Tue, 22 Nov 2011 22:23:00 +0000 Gavin Whitehead
<gavin@alabastercranium.demon.co.uk> wrote:

> I'm not sure if this is a GRUB2 problem or a RAID/MD issue but here goes...
> 
> I want to set up a machine that will boot two Linux installations using 
> raid 1 partitions and Windows XP on a single partition.
> 
> I have two identical disks partitioned as follows
> 
> $ cat /proc/partitions
> major minor  #blocks  name
> 
>     8        0  244198584 sda
>     8        1   30720000 sda1
>     8        2   30720000 sda2
>     8        3   40960000 sda3
>     8        4          1 sda4
>     8        5    4194304 sda5
>     8        6  137601024 sda6
>     8       16  244198584 sdb
>     8       17   30720000 sdb1
>     8       18   30720000 sdb2
>     8       19   40960000 sdb3
>     8       20          1 sdb4
>     8       21    4194304 sdb5
>     8       22  137601024 sdb6
> 
> I installed WinXP first in sda3.
> 
> I then installed Ubuntu 11.04 from the Alternate CD and created some 
> raid1 devices
>      md0        sda1 sdb1    /
>      md1        sda5 sdb5    swap
>      md2        sda6 sdb6    /home
> 
> I set the boot flag on sda1 and sdb1.
> This worked a treat.  I could boot in to either Ubuntu 11.04 to WinXP.  
> I tested the RAID1 (power down, unplug a disk, power up, power down, 
> replug the disk, power up,  use 'mdadm --add' to rebuild the array).  
> Brilliant.
> 
> Then I installed Xubuntu 11.10 from the Alternate CD.  For this install 
> I created one new raid1 device (md3) and reused md1 and md2
>      md3        sda2 sdb2    /
>      md1        sda5 sdb5    swap
>      md2        sda6 sdb6    /home
> 
> I set the boot flag on sda2 and sdb2.
> 
> After the install had completed and grub2 had built the grub.cfg I only 
> had my new Xubuntu 11.10 in the boot menu.  The Xubuntu 11.10 install 
> works perfectly (and I can boot in to Win XP) but I can't boot in to the 
> Ubuntu 11.04 installation.  I've re-run 'update-grub' but it doesn't 
> find the other installation.
> 
> If I run 'sudo mount /dev/md0 /mnt' I can access the Ubuntu 11.04 files.
> 
> Is my intended configuration (tri-boot with two raid1, partition based, 
> Linux installations and XP on a single parition) unachievable?
> 

I would just dive into grub.cfg with an editor and make it work.

These wonderful "automatically make a config file for you tools" certainly
have a place, but there is a reason that config files are plain text files
and that reason is emacs (or possible vim).

NeilBrown

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Re: partition based raid1 and multi boot Ubuntu/Xubuntu

[Gavin Whitehead]

On 22/11/2011 22:45, NeilBrown wrote:
> On Tue, 22 Nov 2011 22:23:00 +0000 Gavin Whitehead
> <gavin@alabastercranium.demon.co.uk>  wrote:
>
>> I'm not sure if this is a GRUB2 problem or a RAID/MD issue but here goes...
>>
>> I want to set up a machine that will boot two Linux installations using
>> raid 1 partitions and Windows XP on a single partition.
>>
>> I have two identical disks partitioned as follows
>>
>> $ cat /proc/partitions
>> major minor  #blocks  name
>>
>>      8        0  244198584 sda
>>      8        1   30720000 sda1
>>      8        2   30720000 sda2
>>      8        3   40960000 sda3
>>      8        4          1 sda4
>>      8        5    4194304 sda5
>>      8        6  137601024 sda6
>>      8       16  244198584 sdb
>>      8       17   30720000 sdb1
>>      8       18   30720000 sdb2
>>      8       19   40960000 sdb3
>>      8       20          1 sdb4
>>      8       21    4194304 sdb5
>>      8       22  137601024 sdb6
>>
>> I installed WinXP first in sda3.
>>
>> I then installed Ubuntu 11.04 from the Alternate CD and created some
>> raid1 devices
>>       md0        sda1 sdb1    /
>>       md1        sda5 sdb5    swap
>>       md2        sda6 sdb6    /home
>>
>> I set the boot flag on sda1 and sdb1.
>> This worked a treat.  I could boot in to either Ubuntu 11.04 to WinXP.
>> I tested the RAID1 (power down, unplug a disk, power up, power down,
>> replug the disk, power up,  use 'mdadm --add' to rebuild the array).
>> Brilliant.
>>
>> Then I installed Xubuntu 11.10 from the Alternate CD.  For this install
>> I created one new raid1 device (md3) and reused md1 and md2
>>       md3        sda2 sdb2    /
>>       md1        sda5 sdb5    swap
>>       md2        sda6 sdb6    /home
>>
>> I set the boot flag on sda2 and sdb2.
>>
>> After the install had completed and grub2 had built the grub.cfg I only
>> had my new Xubuntu 11.10 in the boot menu.  The Xubuntu 11.10 install
>> works perfectly (and I can boot in to Win XP) but I can't boot in to the
>> Ubuntu 11.04 installation.  I've re-run 'update-grub' but it doesn't
>> find the other installation.
>>
>> If I run 'sudo mount /dev/md0 /mnt' I can access the Ubuntu 11.04 files.
>>
>> Is my intended configuration (tri-boot with two raid1, partition based,
>> Linux installations and XP on a single parition) unachievable?
>>
> I would just dive into grub.cfg with an editor and make it work.
>
> These wonderful "automatically make a config file for you tools" certainly
> have a place, but there is a reason that config files are plain text files
> and that reason is emacs (or possible vim).
>
> NeilBrown

Doh.  Obvious really, but thanks for suggesting it.
I have tried it and it works.

Now back to DR testing...

Thanks,

Gav

Re: partition based raid1 and multi boot Ubuntu/Xubuntu

[Gordon Henderson]

On Tue, 22 Nov 2011, Gavin Whitehead wrote:

> I then installed Ubuntu 11.04 from the Alternate CD and created some raid1 
> devices
>    md0        sda1 sdb1    /
>    md1        sda5 sdb5    swap
>    md2        sda6 sdb6    /home

Can't help you with the GRUB issue as I use LILO, however... Something 
that someone on this list suggested to me many year back has stuck with me 
and proven to be useful and that's to try to number the md devices the 
same as the sd (or hd in those days!) devices, so:

md1 : active raid1  sdb1[1] sda1[0]
md2 : active raid10 sdb2[1] sda2[0]
md3 : active raid10 sdb3[1] sda3[0]
md5 : active raid10 sdb5[1] sda5[0]

etc.

Is it still a good idea? I think so - anything that helps to reduce the 
possibility of mistakes is good in my books...

Gordon

Re: partition based raid1 and multi boot Ubuntu/Xubuntu

[Gavin Whitehead]

On 24/11/2011 11:54, Gordon Henderson wrote:
> On Tue, 22 Nov 2011, Gavin Whitehead wrote:
>
>> I then installed Ubuntu 11.04 from the Alternate CD and created some 
>> raid1 devices
>>    md0        sda1 sdb1    /
>>    md1        sda5 sdb5    swap
>>    md2        sda6 sdb6    /home
>
> Can't help you with the GRUB issue as I use LILO, however... Something 
> that someone on this list suggested to me many year back has stuck 
> with me and proven to be useful and that's to try to number the md 
> devices the same as the sd (or hd in those days!) devices, so:
>
> md1 : active raid1  sdb1[1] sda1[0]
> md2 : active raid10 sdb2[1] sda2[0]
> md3 : active raid10 sdb3[1] sda3[0]
> md5 : active raid10 sdb5[1] sda5[0]
>
> etc.
>
> Is it still a good idea? I think so - anything that helps to reduce 
> the possibility of mistakes is good in my books...
>
> Gordon
> -- 
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Gordon,

Thanks for the suggestion.  I will bear it in mind next time I am 
building the raid devices (which I have a feeling will be soon).

Gav