Is there a boot parameter that can be used to disable fake raid detection for 11.1?
Reason is I was installing to an Intel D965GT server mobo yesterday and I wasted an hour or more trying to stop the fake raid support from getting in the way of the software raid install, which was what I wanted. The fake raid show up as /dev/md126 and /dev/md127 and prevent one from assembling raid partitions from the expert dialogues.
Now before you say disable the fake raid in the BIOS, there was no screen to disable it. The user manual says type Ctrl-I at the POST to enter the setup screen. No go. Curse you Intel, other motherboards would definitely have this control.
I tried blacklisting dm-mod but this had no effect.
In the end after steps I cannot retrace now I managed to do mdadm --stop /dev/md126, and also for /dev/md127. Then I could install software raid.
It’s no use suggesting using another CD to partition. The fake raid arrays are created once one goes past the Disk step in the installer and detection of fake raid trumps any software raid partitions one may have created already. Which is why I’m asking if there is a boot parameter to prohibit this autodetection of fake raid.
Not that it matters much since the server is up and running now. Just curious.
You can actually disable the raid functionality in the bios itself (Not the Intel raid bios) - I don’t have the Intel 965DG series of mobo that we use in front of me right now but there was clearly a way to disable the Intel raid completely in the bios.
It was in a funny location, like under the bootable devices or something.
So I was led to believe by the Intel documentation, but I cracked my spectacles looking and looking. My best guess is that there is no extension BIOS for RAID support in the EEPROM. There was a mention of some maintenance software which might possibly flash this option into the EEPROM, but I wasn’t game to tangle with firmware upgrades at that point.
That would be too obvious, but no such option on this motherboard, as I already mentioned. The only options were Configure SATA as Legacy or Enhanced. According to the documentation, after choosing Enhanced one is supposed to be able to use Ctrl-I to configure the RAID features on the next boot, but no way.
Apparently that motherboard ships with a bios that is different to that of most of the Intel boards I’ve seen so far - Cama was spot on with the location of the configuration parameter tho’ - that’s how it’s on 965DG’s and other Intel mobos.
Can you post the exact information that reads on the box regarding the manufacturer and model of the motherboard?
Yes, it’s an old board, at least 3 years old. I should have mentioned that this computer had been running 10.1 with software RAID-1 for the last 3 years and this was an OS upgrade. For 10.1 there was no problem setting up software RAID, because at that time the kernel didn’t support this fake raid hardware. In 11.1 though, the installer was “too helpful” and set up fake raid even though I wanted to use software raid. Hence my question if there is an installer option to say “no, please don’t detect or use fake raid”.
> That would be too obvious, but no such option on this motherboard, as I
> already mentioned. The only options were Configure SATA as Legacy or
> Enhanced. According to the documentation, after choosing Enhanced one is
> supposed to be able to use Ctrl-I to configure the RAID features on the
> next boot, but no way.
If you don’t have such options available, well, contact Intel and ask them
about this, just to be sure you are following the right steps and it’s an
Intel “feature”
Thanks for the attempt to help with the BIOS, and sorry for misleading you with the wrong number. But I’ve pretty much given up on disabling the fake raid feature in this BIOS.
The reason I started this thread is that I feel there ought to be some boot parameter one can pass to the installer to say “don’t try to use fake raid thanks” in case somebody else runs into a similar problem with fake raid on this or any other motherboard. If such an option doesn’t exist, perhaps it should and I’m prepared to file an enhancement request for 11.2 or future.
There is another gotcha with this and probably other BIOSes that I’ll just mention in passing in case someone reads this in future. After the install had completed, it wouldn’t boot off the hard disk, but booting from the DVD and then booting the disk worked. Since all the GRUB stages worked, the issue turned out to be simply that I had to set at least one partition on the primary disk to be bootable. Without this flag, the Intel BIOS silently skips the disk during booting.
> Thanks for the attempt to help with the BIOS, and sorry for misleading
> you with the wrong number. But I’ve pretty much given up on disabling
> the fake raid feature in this BIOS.
>
> The reason I started this thread is that I feel there ought to be some
> boot parameter one can pass to the installer to say “don’t try to use
> fake raid thanks” in case somebody else runs into a similar problem with
> fake raid on this or any other motherboard. If such an option doesn’t
> exist, perhaps it should and I’m prepared to file an enhancement request
> for 11.2 or future.
I am not sure about this, but I think /dev/md* are devices created by what
you mean “software raid” (pure kernel raid) and the so called “fake raid”
uses /dev/dm-* ones.
So, what was the partitioner seeing, “md” devices or “dm” ones? :-?
The partitioner saw /dev/md126 and /dev/md127. dmesg showed that the kernel or a kernel module had put them together. They were not fully functional though, I think one had only one working element. However as mentioned I managed to break up the md devices from the shell and then create my own md0 and md1 in the partitioner. Before that it kept halting the install with an error saying that the disk partition was already in use.
> The partitioner saw /dev/md126 and /dev/md127. dmesg showed that the
> kernel or a kernel module had put them together. They were not fully
> functional though, I think one had only one working element. However as
> mentioned I managed to break up the md devices from the shell and then
> create my own md0 and md1 in the partitioner. Before that it kept
> halting the install with an error saying that the disk partition was
> already in use.
Well, that seems indeed a bug.
You should be able to manage hdds at any level (detect previous arrays,
destroy them and/or create new ones, that’s up to you) within the graphical
environment.
