* aic79xx and RAID ?
@ 2005-12-01 10:20 Hadmut Danisch
2005-12-01 10:37 ` Arjan van de Ven
0 siblings, 1 reply; 6+ messages in thread
From: Hadmut Danisch @ 2005-12-01 10:20 UTC (permalink / raw)
To: linux-scsi
Hi,
I have a question about the aic79xx driver and RAID.
A friend of mine tries to install Linux on a IBM rack server machine,
which has two hard disks and a aic 7902 SCSI/RAID controller.
He has configured both disks as a RAID1 mirror in the BIOS.
However, when booting Linux (SuSE or Knoppix), the kernel recognizes
the controller and loads the aic79xx driver, but does not recognize
the RAID mirror. Instead it presents both disks as separate disks
/dev/sda and /dev/sdb.
I could not find any documentation except that which comes with the
kernel (Documentation/scsi/aic79xx.txt), but it doesn't say anything
about RAID.
Where could I find any hint about how to use RAID disks with aic7902
cards?
regards
Hadmut Danisch
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: aic79xx and RAID ?
2005-12-01 10:20 aic79xx and RAID ? Hadmut Danisch
@ 2005-12-01 10:37 ` Arjan van de Ven
2005-12-01 10:48 ` Hadmut Danisch
0 siblings, 1 reply; 6+ messages in thread
From: Arjan van de Ven @ 2005-12-01 10:37 UTC (permalink / raw)
To: Hadmut Danisch; +Cc: linux-scsi
On Thu, 2005-12-01 at 11:20 +0100, Hadmut Danisch wrote:
> Hi,
>
> I have a question about the aic79xx driver and RAID.
>
> A friend of mine tries to install Linux on a IBM rack server machine,
> which has two hard disks and a aic 7902 SCSI/RAID controller.
ah one of the software raid controllers
> However, when booting Linux (SuSE or Knoppix), the kernel recognizes
> the controller and loads the aic79xx driver, but does not recognize
> the RAID mirror. Instead it presents both disks as separate disks
> /dev/sda and /dev/sdb.
this is in principle the right thing for this kind of software raid.
the dmraid tool is there to support this type of software raid (bios
supported raid) but I don't think it supports adaptec raid yet...
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: aic79xx and RAID ?
2005-12-01 10:37 ` Arjan van de Ven
@ 2005-12-01 10:48 ` Hadmut Danisch
2005-12-01 10:53 ` Arjan van de Ven
2005-12-01 11:39 ` Jeff Garzik
0 siblings, 2 replies; 6+ messages in thread
From: Hadmut Danisch @ 2005-12-01 10:48 UTC (permalink / raw)
To: Arjan van de Ven; +Cc: linux-scsi
Hi,
thanks for the fast reply. :-)
On Thu, Dec 01, 2005 at 11:37:30AM +0100, Arjan van de Ven wrote:
>
> ah one of the software raid controllers
>
..
> this is in principle the right thing for this kind of software raid.
> the dmraid tool is there to support this type of software raid (bios
> supported raid) but I don't think it supports adaptec raid yet...
A software raid controller? Never heard of such a beast before.
I always thought that there are exactly two ways to do raid,
one way is to have it all hidden in the controller, which makes the
RAID mirror appear as just a single disk to the kernel,
and the other way is to use the kernel software raid (configured with
mdadm).
I've never heard of a software raid controller, where the kernel must
do the work itself. After all, what's the controller's job and
why is it called a RAID controller then?
But I guess we have to use software (i.e. kernel driven, mdadm) raid
then?
regards
Hadmut
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: aic79xx and RAID ?
2005-12-01 10:48 ` Hadmut Danisch
@ 2005-12-01 10:53 ` Arjan van de Ven
2005-12-01 11:39 ` Jeff Garzik
1 sibling, 0 replies; 6+ messages in thread
From: Arjan van de Ven @ 2005-12-01 10:53 UTC (permalink / raw)
To: Hadmut Danisch; +Cc: linux-scsi
> ..
> > this is in principle the right thing for this kind of software raid.
> > the dmraid tool is there to support this type of software raid (bios
> > supported raid) but I don't think it supports adaptec raid yet...
>
>
>
> A software raid controller? Never heard of such a beast before.
it's software raid but with support from the cards bios so that you can
boot from it.
> I always thought that there are exactly two ways to do raid,
> one way is to have it all hidden in the controller, which makes the
> RAID mirror appear as just a single disk to the kernel,
> and the other way is to use the kernel software raid
this is basically a correct understanding, and your card is of the
second type.
> (configured with
> mdadm).
there are multiple classes of software raid now; some are driven by
device mapper.
> I've never heard of a software raid controller, where the kernel must
> do the work itself. After all, what's the controller's job and
> why is it called a RAID controller then?
marketing speak... the kernel does all the work. just they sell you a
driver for windows that hides this, as well as a bios rom that allows
you to boot from it.... but other than that it's just software raid.
> But I guess we have to use software (i.e. kernel driven, mdadm) raid
> then?
>
as I said, dmraid (using device mapper) is designed for this type of
software raid...
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: aic79xx and RAID ?
2005-12-01 10:48 ` Hadmut Danisch
2005-12-01 10:53 ` Arjan van de Ven
@ 2005-12-01 11:39 ` Jeff Garzik
2005-12-02 0:32 ` Matthias Andree
1 sibling, 1 reply; 6+ messages in thread
From: Jeff Garzik @ 2005-12-01 11:39 UTC (permalink / raw)
To: Hadmut Danisch; +Cc: Arjan van de Ven, linux-scsi
Hadmut Danisch wrote:
> A software raid controller? Never heard of such a beast before.
>
>
> I always thought that there are exactly two ways to do raid,
> one way is to have it all hidden in the controller, which makes the
> RAID mirror appear as just a single disk to the kernel,
> and the other way is to use the kernel software raid (configured with
> mdadm).
>
> I've never heard of a software raid controller, where the kernel must
> do the work itself. After all, what's the controller's job and
> why is it called a RAID controller then?
Marketing.
Read http://linux.yyz.us/sata/faq-sata-raid.html
Jeff
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: aic79xx and RAID ?
2005-12-01 11:39 ` Jeff Garzik
@ 2005-12-02 0:32 ` Matthias Andree
0 siblings, 0 replies; 6+ messages in thread
From: Matthias Andree @ 2005-12-02 0:32 UTC (permalink / raw)
To: Jeff Garzik; +Cc: Hadmut Danisch, Arjan van de Ven, linux-scsi, rick
Jeff Garzik <jgarzik@pobox.com> writes:
> Hadmut Danisch wrote:
>> A software raid controller? Never heard of such a beast before. I
>> always thought that there are exactly two ways to do raid, one way is
>> to have it all hidden in the controller, which makes the
>> RAID mirror appear as just a single disk to the kernel, and the other
>> way is to use the kernel software raid (configured with
>> mdadm). I've never heard of a software raid controller, where the
>> kernel must
>> do the work itself. After all, what's the controller's job and
>> why is it called a RAID controller then?
>
> Marketing.
>
> Read http://linux.yyz.us/sata/faq-sata-raid.html
Well... your site doesn't list this "HostRAID" euphemism for software
RAID on SCSI ;-)
Seriously, could you add ICH7-R to your fakeraid list, too?
It appears to be software RAID, too.
And perhaps a link to <http://linuxmafia.com/faq/Hardware/sata.html>.
--
Matthias Andree
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2005-12-02 0:32 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-12-01 10:20 aic79xx and RAID ? Hadmut Danisch
2005-12-01 10:37 ` Arjan van de Ven
2005-12-01 10:48 ` Hadmut Danisch
2005-12-01 10:53 ` Arjan van de Ven
2005-12-01 11:39 ` Jeff Garzik
2005-12-02 0:32 ` Matthias Andree
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