Re: LVM & RAID10

[Wojciech Pyczak]

> > (...)The only clue I have is
> > (completly mysterius to me) error message: "We don't support multiple
> > metadata areas".
> >      
>
> Hi,
>
> This error come from lvm, perhaps you can try raid10 first.
>
>    

I played a bit when I had free time and...
 - I learned to ignore grub error messages :D
 - RAID10 seems to work OK
 - LVM @ RAID10 @ single partition (on each disk) results in above 
error message but if I add small partition (so there are 2 partitions 
per disk) there is no error. I tried with different number of LVs, 
different LV names, anything.. could it be some error in grub after all ?

    Anyway even if there is no such error grub doesn't work - it appers 
that core.img doesn't include LVM module (I tried to specify it 
manually) or just doesn't install at all, of course grub-setup return 
some error (unknown root device or something..) but in the other hand I 
saw the same error with root filesystem on RAID device and it actually 
worked.
    There is also another problem: when I installed grub on single HD 
with LVM module in core.img, I couldn't see any LVM devices in the 
system (only hdX, mdX..), I saw something similar on some mailing list 
(debian ?) - removing LVM module then inserting it again fixed that 
problem, however in my case it didn't worked.
    I'm thinking about installing grub by hand, i.e. creating core.img 
and copying it along with boot.img after mbr,  will that work ? (I just 
want to bypass grub-setup).

> Yes, it should work out of the box, although there is a small catch.
> If you're using raid5/raid6 and one/two of the disk is missing or
> corrupted, you need to add module raid5rec/raid6rec using the --module
> option in grub-install.
>    
Just curiosity - why it's in separate modules ?