Re: Drives missing at boot

[Mark Knecht]

On Mon, Jul 5, 2010 at 4:59 PM, Robert Hancock <hancockrwd@xxxxxxxxx> wrote:
> On 07/05/2010 10:48 AM, Mark Knecht wrote:
>>
>> On Sun, Jul 4, 2010 at 11:19 PM, Tejun Heo<tj@xxxxxxxxxx> Âwrote:
>>>
>>> Hello,
>>>
>>> On 07/04/2010 12:31 AM, Mark Knecht wrote:
>>>>
>>>> OK, I don't know if this is related but so far I cannot get the
>>>> machine to boot if I set BIOS SATA configuration to AHCI. I believe
>>>> that I have AHCI support as well as SATA support built into the kernel
>>>> but when I set the BIOS to AHCI the machine just hangs saying it finds
>>>> no medium. I assume that means no hard drive. I have to set SATA
>>>> support to enhanced and then IDE to get the machine to boot at all.
>>>
>>> That's odd. ÂCan you please attach kernel boot log w/ ahci mode?
>>> Booting a recent live CD and saving boot log from there should do the
>>> trick.
>>>
>>> Thanks.
>>>
>>> --
>>> tejun
>>>
>>
>> Hi Tehun,
>> Â ÂThanks for the help.
>>
>> Â ÂI tried a Gentoo install CD from last march. It's a 2.6.31 type
>> kernel. Problem is the buffer depths are not big enough to capture the
>> complete dmesg contents and I don't know a command line option to make
>> it larger on the fly. If you know of one that's got a larger buffer -
>> or a command to increase it at boot time - then let me know and I'll
>> try again.
>>
>> Â ÂI'm attaching what I was able to catch for both AHCI and IDE
>> settings in BIOS for the storage configuration option.
>>
>> Â ÂIt seems to me that even in AHCI mode the machine does see all the
>> hard drives. Maybe there's something about my boot partition that's
>> having problems in AHCI mode only? If it sees /dev/sda then why
>> wouldn't it find grub and at least show a grub menu?
>
> On some machines changing from IDE to AHCI messes up the boot order
> selection in the BIOS - you may have to switch to AHCI, save settings,
> reboot, go back into the BIOS and then make sure the disk boot order
> settings are correct (whatever drive grub is installed on needs to be
> first).
>

That's a very interesting idea Robert. Thanks.

I'll have to be careful. I have 5 identical drives in the machine so
figuring out which is which when I'm in BIOS might be a bit of a
trick.

I'll give it a go and report back.

Cheers,
Mark
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