[conspire] Server supermicro 1U 5013C-MT Raid1

Rick Moen rick at linuxmafia.com
Fri Sep 22 13:28:19 PDT 2006


Quoting Stephan Seelig (sseelig at greenalabs.com):

> that's Stephan and I am an MIS intern at the company GreenAlabs. 
> So I heard from your Cabal meeting/installfest from my supervisor. 

Hi, Stephan.  You might get better and more timely help if you
participate in CABAL's publicly archived mailing list, "conspire".
Information on joining, and access to the public archives, is here:
http://linuxmafia.com/mailman/listinfo/conspire 

I am cc'ing that mailing list, to better benefit the public.

I have only very limited time to help people (especially -- no offence
-- strangers) in private mail.  Please use the mailing list for any
follow-ups.  Thanks.

> And now I am writing to you because I am not allowed to bring the
> company's server to you. I really need some help because my problems
> are slowly beginning to frustrate me.  First I describe you my two
> problems and if you could help me with them I would be so glad.
> 
> OK the first one. I think it has to do with the Bios. Have you ever
> heard from "single bit error location" or "multiple bit error
> location" problems before bios is really starting (after ). This are
> the messages I get during start up. I can continue by physically
> pressing F1 on the severs keyboard.

Well, those diagnostics indicate that some piece of hardware is
generating checksum errors during Power-On Self Test (POST).  It's not
clear from context what piece of hardware that might be.  It could be a
bad stick of RAM.  It could be just some scrambled information in your
motherboard BIOS Setup program's CMOS (non-volatile RAM) data.  It could
be some other piece of hardware that is failing.

Judging by your bit about being able to continue by pressing F1, I would
guess that it's scrambled CMOS data.  Going on that theory, you might
want to pick the BIOS Setup option to re-set BIOS Setup settings to
factory defaults.  That is usually on the same BIOS Setup page where the
exit commands are.

If that doesn't do the trick, you could (1) see if Supermicro has some
diagnostic software for download, tailored for its hardware, and (2)
download the latest BIOS ROM image, and re-flash your BIOS.

> The second problem is with my on board raid 1 system. I want to install
> fedora core 5 on this server (supermicro.com model 5013C-MT)  but I need
> the Linux driver that everything works correct. The architecture of my
> server is i386 a 32bit system but on the web page from super micro there
> are only drivers for i686 architectures. Supermicro is not answering on
> my e-mail by know. May be you have some ideas.

The Supermicro 5013C-MT motherboard uses (among other things) an Intel
6300ESB South Bridge chip, which is of the ICH6 (I/O Controller Hub
version 6) family, to support I/O functions including SATA and PATA
(legacy IDE) hard drives and ATAPI drives (CDs, DVDs).  In that context,
when you say "on-board RAID1 system", you probably are referring to 
Intel's flavour of "fakeraid" (BIOS-assisted software RAID) -- which
should not be confused with genuine hardware RAID, but is all you 
can get at that price point.  Does that sound correct?

If so, ou have your two-drive mirrored pair formatted to a specification
called Intel Software RAID (iswraid), FYI.  iswraid is, pardon my
French, a really crappy, poor substitute for real RAID.  It's
slow-performing, more-or-less Intel-proprietary, and means your drive
pair will be readable only by motherboards containing Intel ICH5 or
later South Bridge chips.  That's what we call "vendor lock-in":
If/when your motherboard fails, you will be obliged to rush out and get
a replacement motherboard (approximately) exactly like it, in order to
ransom your data back.

You _may_ be able to install Fedora Core 5 onto an iswraid array.  That
depends on whether FC5's installation kernel includes the Linux 2.6.x 
"dmraid" driver.  Hmmm, this link at the Fedora Project Wiki suggests
that they haven't gotten around to that, yet:
http://www.fedoraproject.org/wiki/FC5Future#head-88055a6cd6f5ca54fae4f3c162c2f29320772ef8

That will probably come across as bad news, but I would like to suggest
a better alternative:  First, go into your motherboard BIOS and delete
the mirror-pair definition.  (I have never used such a motherboard, so
I'm merely speculating the existence of such a BIOS Setup function.)

Now, you have, once again, just a pair of unmirrored drives.  This is
actually a good thing:  Watch and see.

Now, once again start the Fedora Core 5 installer.  This time, at the
partitioning stage -- Disk Druid or whatever they're calling it, these
days -- select the "Create a software RAID partition" and "Create a RAID
device" options, as described here:
http://fedora.redhat.com/docs/fedora-install-guide-en/fc5/sn-disk-druid.html

What's that about, you might ask?  There is a Linux-native form of
software RAID, sometimes called "md" (the name of the driver, that being
short for "multidevice") or "Linux software RAID":  It is much faster
and more robust than is iswraid, and it is manufacturer independent:
An "md" RAID1 pair, once created, will be readable on any motherboard.

Take your time in the Disk Druid screens, and make sure you understand
what you are doing.  You will be creating two filesystem ("partition") of
the "software RAID" type on each drive (one small one for swap, and
another taking up most of the disk for the root filesystem), and then 
creating a "RAID device" (i.e., a mirror pair) from each corresponding 
pair of software RAID filesystems on each drive.  That will result in 
Linux "devices" addressable as /dev/md0 (for swap) and /dev/md1 (for 
filesapce):  Linux software RAID sets always get assigned names "md"
followed by a numeral, starting with zero.

If memory serves, you then create actual swap partitions 
data-bearing partitions on top of the /dev/md0 and /dev/md1 devices. 

The Fedora installer will probably try to nudge you into using an
abstract-reference layer called LVM (logical volume manager).  If you 
want to use that, fine.  I don't, which is why I make no mention of it,
above.

I hope this is of use to you.  Again, please address any follow-ups 
to the mailing list (which one must join, before one may post there).
 
-- 
Cheers,
Rick Moen                      "vi is my shepherd; I shall not font."
rick at linuxmafia.com                               -- Psalm 0.1 beta




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