Installing Debian on a SuperMicro server

Johann Spies

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Dec 3, 2014, 5:40:05 AM12/3/14

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I am trying to install Debian on a SuperMicro server on two ssd's configured in the bios as a RAID1 (I think it is called a fake-raid).

Debian Stable does not recognize the disks at all.

Debian Testing's installation disk picks it up as a RAID1 device (even when I configure it in the bios as non-raid disks) and can install up to the stage where grub has to be installed. Grub does not recognise the RAID1 device but sees the two disks separately.

When I open gparted in Linuxmint 17 (live imaget) it complains when the disks are configured in bios as RAID1 but gparted sees the separate disks when it is configured as non-raid devices.

I am prepared to go the route of a software raid if necessary, but in the Debian installer that is only possible if the Debian-installer sees the disks as separate disks as Grub does.

Any suggestions for the way forward? Should I put a usb-stick in the server and install grub there?

Regards
Johann

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Miles Fidelman

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Dec 3, 2014, 7:20:03 AM12/3/14

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Johann Spies wrote:
> I am trying to install Debian on a SuperMicro server on two ssd's
> configured in the bios as a RAID1 (I think it is called a fake-raid).
>
> Debian Stable does not recognize the disks at all.
> Debian Testing's installation disk picks it up as a RAID1 device (even
> when I configure it in the bios as non-raid disks) and can install up
> to the stage where grub has to be installed. Grub does not recognise
> the RAID1 device but sees the two disks separately.
>
> When I open gparted in Linuxmint 17 (live imaget) it complains when
> the disks are configured in bios as RAID1 but gparted sees the
> separate disks when it is configured as non-raid devices.
>
>
> I am prepared to go the route of a software raid if necessary, but in
> the Debian installer that is only possible if the Debian-installer
> sees the disks as separate disks as Grub does.
>
> Any suggestions for the way forward? Should I put a usb-stick in the
> server and install grub there?
>
>

Well, my first recommendation would have been turning off BIOS RAID -
but that seems not to work for you. (I've been running SuperMicro
servers for years, always turn off hardware RAID and rely on md - no
SSDs though).

Did a little googling and found this:
https://wiki.debian.org/DebianInstaller/SataRaid - which recommends
adding dmraid=true to the kernel boot line (see page for detailed
instructions).

You might get some good advice on the linux-raid email list. Also, I've
found the webhostingtalk.com forums to be a good source for
product-specific knowledge on various servers - supermicro tech support
is basically useless.

Miles Fidelman

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In practice, there is. .... Yogi Berra

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Johann Spies

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Dec 3, 2014, 9:20:04 AM12/3/14

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Thanks Miles.

Did a little googling and found this: https://wiki.debian.org/DebianInstaller/SataRaid - which recommends adding dmraid=true to the kernel boot line (see page for detailed instructions).

I have tried the procedure in this website, but my results are different. I never got a chance to specify the settings for the partition on the "fake raid". It just used the whole "device" as a partion mounted at /. When I logged in in rescue mode, I could not find the different devices to configure grub.

I have also tried Ubuntu-server 2014-10 but I did not understand the installation asking me whether to activate raid or not for the devices and then not showing them anywhere.

Centos 6.6 could install without a problem but I do not want to work with a rpm-based system if possible.

At the moment Centos or Fedora (which I would not prefer on any server) seems to be the non-commercial options available to me.

Bob Proulx

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Dec 8, 2014, 2:50:04 PM12/8/14

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Johann Spies wrote:
> I am trying to install Debian on a SuperMicro server on two ssd's
> configured in the bios as a RAID1 (I think it is called a fake-raid).

Like Miles recommended I also recommend you avoid BIOS RAID and use
Linux md raid with mdadm instead. I have used Supermicro servers for
years and have always done this.

> Debian Stable does not recognize the disks at all.

That sounds more like a SATA controller problem. Or perhaps the BIOS
is not configured correctly.

> Debian Testing's installation disk picks it up as a RAID1 device (even when
> I configure it in the bios as non-raid disks) and can install up to the
> stage where grub has to be installed. Grub does not recognise the RAID1
> device but sees the two disks separately.

When using software raid (you said "configure it in the bios as
non-raid disks") it is normal to always see two disks individually.
You should use grub to install the MBR to both disks. It is normal at
that point to see /dev/sda and /dev/sdb as raw disks when doing the
grub install. That is the way it works. However the installer has
traditionally only known about the first disk and has only installed
the MBR to the first disk. Installation to the second disk in the
raid has always required a manual installation step.

Is it possible that you rejected the configuration at that point and
didn't continue on through? If so then that is the problem. You
should go ahead and install grub on both /dev/sda and /dev/sdb and
continue on with the installation and reboot.

When I set up a system such as this I always test afterward that the
system can be booted from each disk individually. Don't boot past
grub. Just boot to grub to verify. If you boot past grub into a
degraded raid system it will create a "split brain" problem with each
disk thinking it is newer and requiring the raid to be rebuilt
manually.

> When I open gparted in Linuxmint 17 (live imaget) it complains when the
> disks are configured in bios as RAID1 but gparted sees the separate disks
> when it is configured as non-raid devices.

Again that is normal for parted to see the individual disks. That is
the way software raid works.

> I am prepared to go the route of a software raid if necessary, but in the
> Debian installer that is only possible if the Debian-installer sees the
> disks as separate disks as Grub does.

If the debian-installer does not see both disks individually then that
seems like BIOS RAID was not satisfactorily disabled. If BIOS RAID is
not active then each disk will be seen separately. Then the
debian-installer can set up Linux kernel software raid.

Bob

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mourik jan heupink - merit

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Dec 8, 2014, 3:30:05 PM12/8/14

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On 12/08/2014 08:40 PM, Bob Proulx wrote:
> When I set up a system such as this I always test afterward that the
> system can be booted from each disk individually. Don't boot past
> grub. Just boot to grub to verify. If you boot past grub into a
> degraded raid system it will create a "split brain" problem with each
> disk thinking it is newer and requiring the raid to be rebuilt
> manually.

Or simply change boot priority of the harddisks in the bios? That way
you should be able to fully boot the system from both disks.

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Bob Proulx

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Dec 8, 2014, 8:10:04 PM12/8/14

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mourik jan heupink - merit wrote:
> Bob Proulx wrote:
> > When I set up a system such as this I always test afterward that the
> > system can be booted from each disk individually. Don't boot past
> > grub. Just boot to grub to verify. If you boot past grub into a
> > degraded raid system it will create a "split brain" problem with each
> > disk thinking it is newer and requiring the raid to be rebuilt
> > manually.
>
> Or simply change boot priority of the harddisks in the bios? That way you
> should be able to fully boot the system from both disks.

Not quite. It is possible that the boot sector on one disk points to
the system on the other disk in a criss-cross way. In that case both
disks are required for boot. Swapping the drives in the bios may not
catch that type of problem because both are still online in the
reversed order. Very annoying to find that out later. I say this
because I have had the misfortune to find that out later in just such
circumstance. The debian-installer in rescue mode works well to
recover from such problems.

We were talking Supermicro servers. All of mine have hot swappable
drive bays. (Because I avoid the non-hot-swappable ones. I know
there are a lot of those too.) With hot swap drive bays it is easier
to grab the red handle and pull the drive part way out of the bay to
disconnect it. (Leave it in the bay and let it spin down.) Then you
are assured of the disk isolation.

Bob

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