Re: Software RAID and Fakeraid

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 11/25/2010 11:26 AM, John Sheu wrote:
> What's the preferred way to differentiate BIOS fakeraid from regular
> software mdraid?
>
> I ask this as I'm booting with GRUB2 off a system that has one of
> those Intel fakeraid chipsets.  As of a few months ago, the mdadm
> package has supported these fakeraid setups, so the RAID array comes
> up as a /dev/md### device.  This is unfortunate, as GRUB2 assumes that
> any device of the type /dev/md### must be a pure software RAID device,
> and in util/grub-setup.c:939, tries to install itself to the RAID
> members individually:
>
Right now GRUB2 is unable to distinguish between 2 cases. However you
can inform it that you have scamraid by adding following line to device.map:
(hd0)  /dev/md0

> if (0 && dest_dev[0] == 'm' && dest_dev[1] == 'd'
>     && ((dest_dev[2] >= '0' && dest_dev[2] <= '9') || dest_dev[2] == '/'))
>   {
>     char **devicelist;
>     int i;
>
>     devicelist = grub_util_raid_getmembers (dest_dev);
>
>     for (i = 0; devicelist[i]; i++)
>       {
>         setup (arguments.dir ? : DEFAULT_DIRECTORY,
>                arguments.boot_file ? : DEFAULT_BOOT_FILE,
>                arguments.core_file ? : DEFAULT_CORE_FILE,
>                root_dev, grub_util_get_grub_dev (devicelist[i]), 1,
>                arguments.force, arguments.fs_probe);
>       }
>   }
>
> For a fakeraid setup, however, the BIOS presents the entire device as
> "regular" int13 device, so GRUB2 really should be installing it to the
> entire /dev/md### device, not the individual members.
>
> So what's the preferred way to differentiate BIOS fakeraid?  Is there
> some ioctl that would make this easier than having to parse /proc/mdstat?
>
> Thanks,
> -John Sheu
>
>
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>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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