Does grub support sw raid1?

Does grub support sw raid1?

[Herta Van den Eynde]

(crossposted to linux-raid@vger.kernel.org and redhat-list@redhat.com)
(apologies for this, but this should have be operational last week)

I installed Red Hat EL AS 4 on a HP Proliant DL380, and configured all
system devices in software RAID 1.  I added an entry to grub.conf to 
fallback to the second disk in case the first entry fails.  At boottime, 
booting from hd0 works fine.  As does booting from hd1.

Until I physically remove hd0 from the system.

I tried manually installing grub on hd1,
I added hd1 to the device.map and subsequently re-installed grub on it, 
I remapped hd0 to /dev/cciss/c0d1 and subsequently re-installed grub
all to no avail.

I previously installed this while the devices were in slots 2 and 3. 
The system wouldn't even boot then.  It looks as though booting from sw 
RAID1 will only work when there's a valid device in slot 0.  Still 
preferable over hw RAID1, but even better would be if this worked all 
the way.

Is this working for anyone?  Any idea what I may have overlooked?  Any 
suggestions on how to debug this?

Kind regards,

Herta

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

Re: Does grub support sw raid1?

[Mike Hardy]

This works for me, there are several pages out there (I recall using the
commands from a gentoo one most recently) that show the exact sequence
of grub things you should do to get grub in the MBR of both disks.

It sounds like your machine may not be set to boot off of anything other
than that one disk though? Is that maybe a BIOS thing?

I dunno, but I have definitely pulled a primary drive out of the system
completely and booted off the second one, then had linux come up with
(correctly) degraded arrays

-Mike

Herta Van den Eynde wrote:
> (crossposted to linux-raid@vger.kernel.org and redhat-list@redhat.com)
> (apologies for this, but this should have be operational last week)
> 
> I installed Red Hat EL AS 4 on a HP Proliant DL380, and configured all
> system devices in software RAID 1.  I added an entry to grub.conf to
> fallback to the second disk in case the first entry fails.  At boottime,
> booting from hd0 works fine.  As does booting from hd1.
> 
> Until I physically remove hd0 from the system.
> 
> I tried manually installing grub on hd1,
> I added hd1 to the device.map and subsequently re-installed grub on it,
> I remapped hd0 to /dev/cciss/c0d1 and subsequently re-installed grub
> all to no avail.
> 
> I previously installed this while the devices were in slots 2 and 3. The
> system wouldn't even boot then.  It looks as though booting from sw
> RAID1 will only work when there's a valid device in slot 0.  Still
> preferable over hw RAID1, but even better would be if this worked all
> the way.
> 
> Is this working for anyone?  Any idea what I may have overlooked?  Any
> suggestions on how to debug this?
> 
> Kind regards,
> 
> Herta
> 
> Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Does grub support sw raid1?

[Bill Davidsen]

Mike Hardy wrote:

>This works for me, there are several pages out there (I recall using the
>commands from a gentoo one most recently) that show the exact sequence
>of grub things you should do to get grub in the MBR of both disks.
>
>It sounds like your machine may not be set to boot off of anything other
>than that one disk though? Is that maybe a BIOS thing?
>
>I dunno, but I have definitely pulled a primary drive out of the system
>completely and booted off the second one, then had linux come up with
>(correctly) degraded arrays
>  
>

Frequently a BIOS will boot a 2nd drive if the first is missing/dead, 
but not if it returns bad data (CRC error). A soft fail is not handled 
correctly by all BIOS' in use, possibly a majority of them.

>-Mike
>
>Herta Van den Eynde wrote:
>  
>
>>(crossposted to linux-raid@vger.kernel.org and redhat-list@redhat.com)
>>(apologies for this, but this should have be operational last week)
>>
>>I installed Red Hat EL AS 4 on a HP Proliant DL380, and configured all
>>system devices in software RAID 1.  I added an entry to grub.conf to
>>fallback to the second disk in case the first entry fails.  At boottime,
>>booting from hd0 works fine.  As does booting from hd1.
>>
>>Until I physically remove hd0 from the system.
>>
>>I tried manually installing grub on hd1,
>>I added hd1 to the device.map and subsequently re-installed grub on it,
>>I remapped hd0 to /dev/cciss/c0d1 and subsequently re-installed grub
>>all to no avail.
>>
>>I previously installed this while the devices were in slots 2 and 3. The
>>system wouldn't even boot then.  It looks as though booting from sw
>>RAID1 will only work when there's a valid device in slot 0.  Still
>>preferable over hw RAID1, but even better would be if this worked all
>>the way.
>>
>>Is this working for anyone?  Any idea what I may have overlooked?  Any
>>suggestions on how to debug this?
>>
>>Kind regards,
>>
>>Herta
>>
>>Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
>>

-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979

Re: Does grub support sw raid1?

[Herta Van den Eynde]

Thanks to all who confirmed that this should work, and gave pointers to 
   more reading material.

Further investigation proved that the problem is caused by the Smart 
Array Controllers that HP uses.  As these "Smart" controllers don't 
allow for JBOD configs, I had configured each disk as RAID 0 at the 
hardware level.  When I remove disk 0, the controller detects that it is 
not set up for fault tolerance, and fails the logical drive.
As they apparently will only boot from the first logical drive defined, 
(which must have been the reason why I couldn't boot when I installed 
Red Hat on drives in slots 2 and 3), you now need to go into the Smart 
controller configuration utility, and delete the failed logical drive.
My 2nd disk was configured in logical drive 2, which now is at the top 
of the list, and therefore can boot just fine.

I'm now struggling with getting the Smart Array controller to recognize 
the replacement devive, but that would be a question for an HP/linux 
mailing list.  I tried registering to 
compaqandlinux-subscribe@van-dijk.net, which gets expanded to 
compaqandlinux-subscribe@jedi.van-dijk.net, but that comes back with a 
"user unknown in local recipient table".
Does anyone know of a good "linux on HP" mailinglist?

Kind regards,

Herta


Mike Hardy wrote:
> This works for me, there are several pages out there (I recall using the
> commands from a gentoo one most recently) that show the exact sequence
> of grub things you should do to get grub in the MBR of both disks.
> 
> It sounds like your machine may not be set to boot off of anything other
> than that one disk though? Is that maybe a BIOS thing?
> 
> I dunno, but I have definitely pulled a primary drive out of the system
> completely and booted off the second one, then had linux come up with
> (correctly) degraded arrays
> 
> -Mike
> 
> Herta Van den Eynde wrote:
> 
>>(crossposted to linux-raid@vger.kernel.org and redhat-list@redhat.com)
>>(apologies for this, but this should have be operational last week)
>>
>>I installed Red Hat EL AS 4 on a HP Proliant DL380, and configured all
>>system devices in software RAID 1.  I added an entry to grub.conf to
>>fallback to the second disk in case the first entry fails.  At boottime,
>>booting from hd0 works fine.  As does booting from hd1.
>>
>>Until I physically remove hd0 from the system.
>>
>>I tried manually installing grub on hd1,
>>I added hd1 to the device.map and subsequently re-installed grub on it,
>>I remapped hd0 to /dev/cciss/c0d1 and subsequently re-installed grub
>>all to no avail.
>>
>>I previously installed this while the devices were in slots 2 and 3. The
>>system wouldn't even boot then.  It looks as though booting from sw
>>RAID1 will only work when there's a valid device in slot 0.  Still
>>preferable over hw RAID1, but even better would be if this worked all
>>the way.
>>
>>Is this working for anyone?  Any idea what I may have overlooked?  Any
>>suggestions on how to debug this?
>>
>>Kind regards,
>>
>>Herta
>>
>>Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
>>
>>-
>>To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>>the body of a message to majordomo@vger.kernel.org
>>More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
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> 

-- 
Herta Van den Eynde              -=- Toledo system management
K.U. Leuven - Ludit              -=- phone: +32 (0)16 322 166
                                  -=- 50°51'27" N 004°40'39" E

"Life on Earth may be expensive,
  but it comes with a free ride around the Sun."

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

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