what RAID levels does GRUB2 support?

what RAID levels does GRUB2 support?

[Tomasz Chmielewski]

According to http://grub.enbug.org/LVMandRAID, "GRUB has support for LVM 
and RAID since version 1.95" and "Installing GRUB while /boot is on RAID 
and/or LVM should be straightforward".

However, it doesn't specify what RAID levels are supported.

RAID-1 is certainly supported. What about other RAID levels, like 
RAID-5, RAID-0 or RAID-10?

Will GRUB2 boot a Linux system from such RAID levels without a separate 
/boot partition?


-- 
Tomasz Chmielewski
http://wpkg.org

Re: what RAID levels does GRUB2 support?

[Felix Zielcke]

Am Donnerstag, den 09.10.2008, 10:12 +0200 schrieb Tomasz Chmielewski:
> According to http://grub.enbug.org/LVMandRAID, "GRUB has support for LVM 
> and RAID since version 1.95" and "Installing GRUB while /boot is on RAID 
> and/or LVM should be straightforward".
> 
> However, it doesn't specify what RAID levels are supported.
> 
> RAID-1 is certainly supported. What about other RAID levels, like 
> RAID-5, RAID-0 or RAID-10?
> 
> Will GRUB2 boot a Linux system from such RAID levels without a separate 
> /boot partition?
the SVN version supports everything from the Linux Software RAID
RAID 0,1,10,4,5,6 and multipath which is just mapped to RAID 1 in
grub2's code

Re: what RAID levels does GRUB2 support?

[Dave Abrahams]

Felix Zielcke <fzielcke <at> z-51.de> writes:

> > Will GRUB2 boot a Linux system from such RAID levels without a separate 
> > /boot partition?
>
> the SVN version supports everything from the Linux Software RAID
> RAID 0,1,10,4,5,6 and multipath which is just mapped to RAID 1 in
> grub2's code

Sooo... 

* Will GRUB2 boot a linux system from RAID5 without a separate /boot partition?

* Has anyone posted a HOWTO about that?  

I tried and failed to configure such a system.  I wouldn't mind being the first
to write such a HOWTO if I could get some handholding from this group :-)

Re: what RAID levels does GRUB2 support?

[Felix Zielcke]

Am Sonntag, den 01.02.2009, 01:48 +0000 schrieb Dave Abrahams:

> Sooo... 
> 
> * Will GRUB2 boot a linux system from RAID5 without a separate /boot partition?

This should work yes.

> * Has anyone posted a HOWTO about that?  
> 
> I tried and failed to configure such a system.  I wouldn't mind being the first
> to write such a HOWTO if I could get some handholding from this group :-)

There shouldn't be anything special needed. Just make your RAID 5 and
then do: grub-install "md0"
in case /dev/md0 is your RAID5 and then GRUB2 gets installed onto every
disk in the MBR.

-- 
Felix Zielcke

Re: what RAID levels does GRUB2 support?

[Wojciech Pyczak]

Dnia 2009-02-01, nie o godzinie 09:19 +0100, Felix Zielcke pisze: 
> Am Sonntag, den 01.02.2009, 01:48 +0000 schrieb Dave Abrahams:
> 
> > Sooo... 
> > 
> > * Will GRUB2 boot a linux system from RAID5 without a separate /boot partition?
> 
> This should work yes.
> 
> > * Has anyone posted a HOWTO about that?  
> > 
> > I tried and failed to configure such a system.  I wouldn't mind being the first
> > to write such a HOWTO if I could get some handholding from this group :-)
> 
> There shouldn't be anything special needed. Just make your RAID 5 and
> then do: grub-install "md0"
> in case /dev/md0 is your RAID5 and then GRUB2 gets installed onto every
> disk in the MBR.
> 

Yet another RAID related question, I decided to try out RAID partitions
(using grub svn versions), basically I've such disk layout:

md0: (RAID10 on 2 of 3 disks - /dev/sda1, /dev/sdb1)
   md0p1 - ext2, /boot
   md0p2 - reiserfs, /
   md0p3 - LVM2


Grub-mkconfig worked as expected detecting:

menuentry "GNU/Linux, linux 2.6.28.3" {
        insmod raid mdraid
        set root=(md0p1)
        linux   /vmlinux-2.6.28.3 root=/dev/md0p2 ro  
}


However grub-install /dev/(md0 | /dev/md0p1 | /dev/sda | /dev/sdb) throw
some errors(every time the same): 

grub-probe: error: no mapping exists for `md0p1'
Auto-detection of a filesystem module failed.
Please specify the module with the option `--modules' explicitly.

I tried using --modules="raid mdraid" but it didn't help much:

grub-probe: error: no mapping exists for `md0p1'
error: We don't support multiple metadata areas
Invalid device `md0'.
Try ``grub-setup --help'' for more information.


Error about multiple metadata is something which I reported here before
(related to LVM) but it doesn't really matter since grub isn't installed
at all (well, I suppose so at least). 

Is there any trick to make it work or is partitioned raid support still
work in progress ?

Re: what RAID levels does GRUB2 support?

[Felix Zielcke]

Am Samstag, den 07.02.2009, 23:07 +0100 schrieb Wojciech Pyczak:

> 
> Yet another RAID related question, I decided to try out RAID partitions
> (using grub svn versions), basically I've such disk layout:
> 
> md0: (RAID10 on 2 of 3 disks - /dev/sda1, /dev/sdb1)
>    md0p1 - ext2, /boot
>    md0p2 - reiserfs, /
>    md0p3 - LVM2
> 
> 
> Grub-mkconfig worked as expected detecting:
> 
> menuentry "GNU/Linux, linux 2.6.28.3" {
>         insmod raid mdraid
>         set root=(md0p1)
>         linux   /vmlinux-2.6.28.3 root=/dev/md0p2 ro  
> }
> 
> 
> However grub-install /dev/(md0 | /dev/md0p1 | /dev/sda | /dev/sdb) throw
> some errors(every time the same): 
> 
> grub-probe: error: no mapping exists for `md0p1'
> Auto-detection of a filesystem module failed.
> Please specify the module with the option `--modules' explicitly.
> 
> I tried using --modules="raid mdraid" but it didn't help much:
> 
> grub-probe: error: no mapping exists for `md0p1'
> error: We don't support multiple metadata areas
> Invalid device `md0'.
> Try ``grub-setup --help'' for more information.
> 
> 
> Error about multiple metadata is something which I reported here before
> (related to LVM) but it doesn't really matter since grub isn't installed
> at all (well, I suppose so at least). 
> 
> Is there any trick to make it work or is partitioned raid support still
> work in progress ?
> 
Then you used revision < 1973
/dev/mdNpN style devices are supported since 1937

-- 
Felix Zielcke