Re: getting a linux boot loader (preferably grub) installed on an intel imsm raid

["K. Posern" <quickhelp@gmail.com>]

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Hi Dave,

Thanks for your answer!

On 19/08/10 17:40, Jiang, Dave wrote:
>> -----Original Message-----
>> Subject: Re: getting a linux boot loader (preferably grub) installed on
>> But I am really stuck alone, so I am willing to throw a Fedora on my
>> machine if in exchange I would get the grub commands to make grub boot
>> my intel RAID-0 :)
>
> Well theoretically the OROM would present the RAID volume to the bootloader as a disk that it can read from. So if you mark your RAID volume for booting in BIOS, it should be able to pick up the bootloader from there right? Are you not able to install to /dev/md127 or whatever device node your RAID volume is on?
No. That is exactly the problem here. As mentioned in my original posting:

         *** For grub2: The default way to install it: grub-install 
/dev/md126 (= imsm volume) just returns 3 error messages.
      Even though the bzr version of grub2 does support mdadm.imsm raids 
with metada version >=1.2, it does /not/ support mdadm raids which are 
partitioned.
So I would need to put /dev/md126 into device.map (as the OROM of the 
intel fakeraid will assemble the raid-0 for grub to access it as a 
normal drive) and I need to install grub2 on the RAID-0 Volume 
/dev/md126! ... But how?
     As I am quiet new to grub2 it would be very helpful to get an idea 
of what of the (many) tools to use and if possible with what parameters.
     Plus I wonder if with grub2 there will be problems because grub2 
will try to assemble the RAID itsself.

         *** For grub: I did quite some installations but all my trials 
to install grub to /dev/md126 (= imsm Volume) did always end in an Error 
22 on "setup (hd0)" in the grub shell. <<< If grub would be your 
recommendation I can post the details!

> Also technically the imsm RAID is not fakeraid because it uses MDRAID instead of special driver to "fake" RAID in Linux. It's just Linux software RAID with OROM support.
I am not sure about the /official/ definition of the term "fakeraid". I 
would have said that because you can create/delete the RAID within the 
OROM (so without any Operating System (e.g. Software-RAID Program 
involved) --> "Fakeraid".

Actually: Is there any hardware support within the:
   00:1f.2 RAID bus controller: Intel Corporation Mobile 82801 SATA RAID 
Controller (rev. 05)
Like an xor chip that is used to outsource some of the work under 
windows, but not under linux (because as you stated: as under linux 
there is no special driver, but linux uses mdadm to access to access the 
container and the volume)?
If yes, are there any plans to develop a driver to outsource the xors to 
the RAID chip for Linux?

Knuth


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