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List:       suse-autoinstall
Subject:    Re: [suse-autoinstall] Suse 9.0 on Raid mirror - include external driver module
From:       "Carl Peto" <carl () bookmanassociates ! com>
Date:       2004-04-15 7:39:57
Message-ID: 00bb01c422bc$dc657850$0c00a8c0 () bill
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I hope that you're not feeling too bad today!

I've successfully installed RAID on a very similar setup to the one you are
using so I expect that we can work this out.

I had a motherboard with a Highpoint based chipset on it.  These are similar
to the Promise chipset you describe.  In both cases the chipset doesn't
"really" do RAID.  Instead it is really much like a normal dual IDE
interface and the RAID mirroring or striping is being done by a driver in
software.  The physical difference is down to some resistor somewhere (I
have heard).  Plus there is a BIOS interface that you can activate by
pressing Ctrl-H when you boot, allowing you to go into a BIOS type blue and
white (or was it yellow?) screen that enables you to define RAID1 mirrors,
RAID0 stripe sets, create and break mirrors, etc.

The driver is then supposed to take over where the BIOS left off when the
operating system gets started.  As I understand it this means that these
"semi-software" RAID systems work in a fundamentally different way from what
I had traditionally regarded as RAID.

For a RAID 1 mirror (for instance) on a "real" or "hardware" RAID solution,
the operating system (be it Windows 3.1, DOS, FreeBSD, Slackware Linux,
Fedora Core, SuSE Linux, Windows ME or Windows 2003 Server) sees what looks
to it like one normal hard disk on one of it's SCSI interfaces (not aware if
this "hardware" RAID ever exists on IDE but if so then the "disk" would
appear as a master or slave on one of the IDE interfaces).  When the OS
writes a block to the hard drive the data is in fact sent to a
microcontroller on the RAID card.  This microcontroller then decides what to
do with the block, based on how the actual physical disks attached to the
card are configured, in the case of RAID1 it will write the block to both
disks, or if reading, will decide one disk to read from (based on the head
that is currently nearest).

On a "semi-software" card (or motherboard) like the Promise and Highpoint
based ones all this work is done by the operating system driver.  The
operating system can actually see both disks in a RAID1 mirror as normal,
seperate disks.  (You can often see this in the custom partitioning section
of YaST as two separate disks, perhaps /dev/hde and /dev/hdg.)

There are a few consequenses to this (as I learned to my cost earlier this
year).  Firstly the Promise/Highpoint are a lot cheaper to buy, which is why
we got them, when we didn't know the difference.  Secondly they usually
don't support RAID4 or 5, although I guess that may change as I can't see
any reason why they can't in principle.  Thirdly your OS driver *must* be
100% supported, stable and reliable.

To my cost I installed a Linux driver that should have worked on one of our
business systems.  Thank God we had a good backup solution in place, it
worked beautifully for a day or so then merrily trashed the drive in
question which had to be rebuilt from scratch.  Who knows, maybe I didn't
have exactly the perfect version of the driver or maybe I needed to perform
some undocumented step to ensure that this didn't happen.  Anyway you get my
point, I'm a Linux sysadmin, not a developer, I don't get paid to install
stuff that will trash our precious business data.

Because this setup operates in software...
1) you must have working drivers for all OS partitions
2) these partitions will be mirrored independantly, the driver on Windows
2000 will work seperately from the one on Linux
3) the performance will be no better than any other software RAID, quite
possibly the performance will be worse

With Win 2003 (at least) this works pretty much transparently as you have
seen.



With Linux what I'd recommend is that you forget about the Promise driver
and use the Software RAID capabilities built into SuSE Linux.   The
configuration guide should give you enough help on how to do this, if not
then by all means come back to this list for help.

I switched to standard Linux Software RAID and I've literally never looked
back, I do not miss the BIOS utility and the nagging concern that the 3rd
party driver might mess up and trash my disks any day.  Remember that the
Software RAID in Linux has effectively been far more thoroughly tested than
the Linux driver that Promise supply.


Good luck,
Carl Peto

----- Original Message ----- 
From: "Eveline Bernard" <ebernard@denkster.nl>
To: <suse-autoinstall@suse.com>
Sent: Wednesday, April 14, 2004 5:27 PM
Subject: [suse-autoinstall] Suse 9.0 on Raid mirror - include external
driver module


Please help me install Suse 9 on a new Raid system!
It is driving me MAD!

I noticed several unsolved issues on this newsforum, about Raid, External
modules.
Please let some more experienced Linux crack dive into it and solve it, I'm
a newbe on Linux.

The Yast2 should ask for the external driver module, but it does not.
Hèèlup!

My system is
Asus P4C800-E Deluxe motherboard with Promise FasTrak 378 controller.
I attached two Maxtor 80 GB SATA disks in Raid mirror configuration.
The system has also an Adaptec 2940 SCSi controller, with Plextor CD-Writer
and Iomega Zip 100 drive attached.
And to the on-board USB 2.0 controller an multimedia card reader is
attached.
There is an Plextor DVD RW on the EIDE controller.

I partitioned the Raid disks in 3 NTFS and 1 Ext3 partition.
On one NTFS  partition Windows 2000 is succesfully running.
I want to install Suse 9.0 on an ext3 partition.

I downloaded the file 1_ft3xssb19.zip file, containing the FasTrack S150
TX2plus driver for Suse 9.0 from Promise, since the FasTrak 378 OEM
controller is the same, according to Promise.
I unpacked it and put it on a floppy disk, as the manual says.
I put the Suse 9.0 CD #1 in the CD drive, start the PC.
The system boots from the CD, while I press the F3 key (as the manual says
to do)
The Suse Installation screen appears and I Enter on the option
"Installation".

@@@>The YASt2 should now ask for the floppy. But it does not!<@@@

It does not matter if I insert the floppy before or afterwards.
The diskette is read for a second, when inserted. But the module seems not
toe be loaded.
I tried again with a diskette where the driver module is in the root - no
result either.

Yast2 does not find my Raid disks, whatever I try.
(Error)
So Yast givess no configuration proposal.
I also tried left Alt key instead of F3 key.
I also tried "Installation - safe settings" - no result
I also installed "Installation" with ACPI = Off in the boot options - no
result
I also tried, after a no result installation effort, to click the button
"cancel installation.
A smaller Main menu window appears. I choose option "Start Installation /
system"
Then I push OK, select Installation, and Ok again, a menu appears: choose
source medium. But choices are CD-Rom, Network, Hard disk
When I choose Harddisk I can fill in several partitions.
Not any of my choices had result: "error could not mount the specified
partition"
When I choose CD-Rom and have the F3 key pressed the same useless round
starts, with one difference:
there is a window asking "confirm driver activation"
"Yast2 has detected the following device: Promise Technology Inc (Asustek
Computer Inc) Driver module to load"
and then there is a window with "pdcraid"
I can click OK or cancel. Both to no result.
On OK I get a similar window about usb storage and then another one about
sbp2 protocol.
What should I do wih these? Do I have to enter something?

The whole thing drives me raving mad. Please help..


Eveline Bernard
'Denkster'


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