Raid auto-assembly on LDM?

Raid auto-assembly on LDM?

[Jan De Luyck]

Hello folks,

I'm trying something which is probably slightly crazy, but I can't get it to work.

What I'm trying is to get the linux kernel to auto-assembly my raid-1 sets, 
which are based on volumes on two LDM disks.

The problem is that the kernel looks for partitiontypes of 0xfd, which I can't 
set (or haven't found yet how to set) for LDM volumes. The assembly fails, and 
the kernel panics.

Another possibility would be to use an initrd/initramfs, but then I'm once again 
stuck with a disk that is not in raid, and ergo a point of failure when the disk 
might crash.

(The reason to use LDM is that this way I also can put the other OS on the disk 
in mirror.)

Does anyone have any other ideas? I've searched the web, but noone really seems 
inclined to do it this way...

Kind regards,

Jan

Re: Raid auto-assembly on LDM?

[Neil Brown]

On Sunday June 15, ml_linuxkernel_20060528@kcore.org wrote:
> Hello folks,
> 
> I'm trying something which is probably slightly crazy, but I can't get it to work.
> 
> What I'm trying is to get the linux kernel to auto-assembly my raid-1 sets, 
> which are based on volumes on two LDM disks.
> 
> The problem is that the kernel looks for partitiontypes of 0xfd, which I can't 
> set (or haven't found yet how to set) for LDM volumes. The assembly fails, and 
> the kernel panics.

Sorry, acronym failure:  What is LDM??

> 
> Another possibility would be to use an initrd/initramfs, but then I'm once again 
> stuck with a disk that is not in raid, and ergo a point of failure when the disk 
> might crash.

I don't understand your conclusion.
The initrd/initramfs is stored where ever your kernel is stored.  If
storing an initrd introduces a single point of failure, then storing
your Linux kernel will too.


Confused.

NeilBrown 


> 
> (The reason to use LDM is that this way I also can put the other OS on the disk 
> in mirror.)
> 
> Does anyone have any other ideas? I've searched the web, but noone really seems 
> inclined to do it this way...
> 
> Kind regards,
> 
> Jan
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Re: Raid auto-assembly on LDM?

[Jan Engelhardt]

On Thursday 2008-06-19 06:29, Neil Brown wrote:
>On Sunday June 15, ml_linuxkernel_20060528@kcore.org wrote:
>> Hello folks,
>> 
>> I'm trying something which is probably slightly crazy, but I can't get it to work.
>> 
>> What I'm trying is to get the linux kernel to auto-assembly my raid-1 sets, 
>> which are based on volumes on two LDM disks.
>> 
>> The problem is that the kernel looks for partitiontypes of 0xfd, which I can't 
>> set (or haven't found yet how to set) for LDM volumes. The assembly fails, and 
>> the kernel panics.
>
>Sorry, acronym failure:  What is LDM??

Logical Device Manager... that Windows thing (CONFIG_LDM_PARTITION)