Mailing List Archive: how to boot from scsi with grub

how to boot from scsi with grub

Oct 20, 2004, 4:20 PM

Post #1 of 3 (237 views)

im confused as to how to boot from my scsi with grub, does it still use
hd0,0 with scsi or does it change to sd0,0? the docs say that grub
doesnt know ide from scsi but it says the scsi numbers should be higher,
are they talking about LUNS? i have the first scsi disk on id0 and there
is no ide controller in the machine, so should i use hd0,0 still? almost
at the reboot part of the install and dont want to screw up now, thanks
for the help.

nick

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Re: how to boot from scsi with grub [ In reply to ]

neil at ep

Oct 20, 2004, 8:41 PM

Post #2 of 3 (231 views)

Permalink

Nick Smith wrote:

> im confused as to how to boot from my scsi with grub, does it still use
> hd0,0

Yes.

> with scsi or does it change to sd0,0? the docs say that grub
> doesnt know ide from scsi but it says the scsi numbers should be higher,

Grub only knows what the BIOS tells it - no drivers are loaded at that
stage. So, with a pure SCSI system, your first SCSI drive will be hd0 as
far as Grub is concerned.

> are they talking about LUNS?

No. In most mixed IDE/SCSI systems, the IDE hard drives will take the
first numbers.

> i have the first scsi disk on id0 and there is no ide controller in the
> machine, so should i use hd0,0 still?

Yep.

Be lucky,

Neil

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Re: how to boot from scsi with grub [ In reply to ]

heinz.sporn at sporn-it

Oct 20, 2004, 10:31 PM

Post #3 of 3 (239 views)

Permalink

That is not quite correct in every case. If you have for example a
couple of SCSI drives with LUN 0, 2, 3, 5 and you adviced your
controller to boot from LUN3 then Grub will recognize this drive as
hd0,0 AT BOOT-TIME. So at least for SCSI (and BTW also for USB storage)
devices the boot device will always be hd0,0.

Neil Walker schrieb:
>
>
> Nick Smith wrote:
>
>> im confused as to how to boot from my scsi with grub, does it still
>> use hd0,0
>
>
> Yes.
>
>> with scsi or does it change to sd0,0? the docs say that grub
>> doesnt know ide from scsi but it says the scsi numbers should be higher,
>
>
> Grub only knows what the BIOS tells it - no drivers are loaded at that
> stage. So, with a pure SCSI system, your first SCSI drive will be hd0 as
> far as Grub is concerned.
>
>> are they talking about LUNS?
>
>
> No. In most mixed IDE/SCSI systems, the IDE hard drives will take the
> first numbers.
>
>> i have the first scsi disk on id0 and there is no ide controller in the
>> machine, so should i use hd0,0 still?
>
>
> Yep.
>
>
> Be lucky,
>
> Neil
>
>
>
> --
> gentoo-user@gentoo.org mailing list
>
>
>

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