Re: [gentoo-server] Can't mount root device (PERC 5/i)

[Steve Dommett]

Patrik Jansson wrote:
> I'm not sure how to do that. I'm not even sure if /dev/sdb is the
> actual RAID or just one of the drives?
The kernel is telling you the size of the disk it sees. Can you not
deduce the answer to your question from this info?

> SCSI device sda: 285474816 512-byte hdwr sectors (146163 MB)
>
Is that the correct total size of the logical drive, or of one of the
physical drives?
I'm pretty sure that's your logical drive right there.   Which would
indicate the megaraid_sas driver seems to working just fine.

> But when I come to think about it... when I try to boot the system,
> the Dell server actually boots from the logical drive and it do find
> the kernel, hence /dev/sdb is infact the RAID, right?
I believe even Dell BIOSes will be using the old DOS-style INT13h
extensions to read the MBR.  As will grub.  But then the kernel will
re-initialise the hardware and drive it directly, rather than asking the
BIOS for help.  This is why you get to load the kernel and then fail.


> > Also, I doubt if this is necessary with a hardware RAID controller,
> > but perhaps emerge'ing device-mapper is necessary.   Perhaps also
> > mdadm too, but I'm even more doubtful about that one.
>
> I can't see how this could make any difference when I can't even mount
> the root device? Anyway, I'm desperate and will try this as soon as I
> can.
>
Yes, that was just a stab in the dark.   More caffeine has now proven to
me how foolish that must have sounded.

But, unabashed, I shall offer another stab in the dark:    is it
possible this new server is using an EFI partition table, rather than
MS-DOS compatible?   Try to ensure CONFIG_EFI _PARTITION is set in your
kernel.

Take care folks,
  Steve.
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