Re: [gentoo-amd64] How to install to a RAID set?

Re: [gentoo-amd64] How to install to a RAID set?

[Mike Williams]

On Saturday 06 May 2006 21:18, Peter Humphrey wrote:
> The instructions say to enclose the parameter in quotes, but when I did
> that it complained Unknown ""-ay". Omitting the quotes enabled it to
> connect to the array (that isn't the word, but I'm not at that screen at
> the moment) and give every appearance of knowing what it's doing. But then
> when I run fdisk -l I see two 200GB disks /dev/sda and /dev/sdb, not the
> single 400GB disk I expect. Clearly, installing to /dev/sda isn't going to
> get me very far - not only will it not be the RAID array I want, but I dare
> say it'll break the array that the BIOS has created and WinXP is happily
> using.

The raid array will be a different device to the individual disks.

> I've googled all over the place, looking for clues. That's right - I don't
> have any ;-(

Check dmesg for info, or have a poke around in /dev.

> Can anyone here help out? Even knowing the format of the name dmraid
> expects for an existing array would help, but I can't find anything
> anywhere.

Do you actually need windows to access it too?
If not, scrap dmraid, and use plain old linux software raid.

-- 
Mike Williams
-- 
gentoo-amd64@gentoo.org mailing list

Re: [gentoo-amd64] How to install to a RAID set?

[Nuitari]

> So I plugged the drives in and started exploring (they're 2 x 200 GB Maxtor
> SATA disks). After many attempts I now have a new WinXP installation on the
> new RAID-0 set, and all looks fine there. But after innumerable attempts and
> much hair tearing I still have no trace of Gentoo. I've eventually
> discovered that I need to pass "dmraid=X" to the installer at CD-boot time,
> but the instructions are both wrong and unhelpful in telling me what X is. I
> did manage to read "man dmraid" (though not print it - anyone know how to
> print Linux man pages on a Windows box?) from which it seemed I needed an
> -ay paramter, thus:

After quite a few experience with most software RAID that require drivers 
I have come to the conclusion that they are not worth anything. You are 
much better off using Linux software raid which will work even if you 
change chipsets, as in upgrading your computer in a later point in time.
Also there are quite a few software Raid out there that require you to 
rebuild the Raid if you ever update the Bios.

I would only use only actual real Hardware RAID such as an IBM ServeRaid 
card.

If you need raid in Windows XP I think that it also supports a virtual 
Raid system, I have never used it so ymmv.
-- 
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[gentoo-amd64] How to install to a RAID set?

[Peter Humphrey]

Well, here's a pretty kettle of fish, and no mistake.

Having had this dual-Opteron box for over two years with just plain IDE
disks, I decided it was time to bite the bullet and plug in a couple of
SATAs. So I did. The motherboard has a VIA chipset with what turns out to be
firmware RAID, though I had thought in my innocence that anything in the
chipset would be hardware - hah! Windows drivers for the interface are
supplied, but apparently Linux kernels need libata compiled in and dmraid
installed. Gentoo 2006.0 installation CD has both, so I should be ready to
go.

So I plugged the drives in and started exploring (they're 2 x 200 GB Maxtor
SATA disks). After many attempts I now have a new WinXP installation on the
new RAID-0 set, and all looks fine there. But after innumerable attempts and
much hair tearing I still have no trace of Gentoo. I've eventually
discovered that I need to pass "dmraid=X" to the installer at CD-boot time,
but the instructions are both wrong and unhelpful in telling me what X is. I
did manage to read "man dmraid" (though not print it - anyone know how to
print Linux man pages on a Windows box?) from which it seemed I needed an
-ay paramter, thus:

gentoo dodmraid=-ay

The instructions say to enclose the parameter in quotes, but when I did that
it complained Unknown ""-ay". Omitting the quotes enabled it to connect to
the array (that isn't the word, but I'm not at that screen at the moment)
and give every appearance of knowing what it's doing. But then when I run
fdisk -l I see two 200GB disks /dev/sda and /dev/sdb, not the single 400GB
disk I expect. Clearly, installing to /dev/sda isn't going to get me very
far - not only will it not be the RAID array I want, but I dare say it'll
break the array that the BIOS has created and WinXP is happily using.

I've googled all over the place, looking for clues. That's right - I don't
have any ;-(

Can anyone here help out? Even knowing the format of the name dmraid expects
for an existing array would help, but I can't find anything anywhere.

--
Rgds
Peter.


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Re: [gentoo-amd64] How to install to a RAID set?

[Boyd Stephen Smith Jr.]

[-- Attachment #1: Type: text/plain, Size: 482 bytes --]

On Saturday 06 May 2006 15:18, Nuitari <nuitari@melchior.nuitari.net> wrote 
about 'Re: [gentoo-amd64] How to install to a RAID set?':
> I would only use only actual real Hardware RAID such as an IBM ServeRaid
> card.

Or any one of the Areca line.

-- 
"If there's one thing we've established over the years,
it's that the vast majority of our users don't have the slightest
clue what's best for them in terms of package stability."
-- Gentoo Developer Ciaran McCreesh

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Re: [gentoo-amd64] How to install to a RAID set?

[Neil Stone]

Nuitari wrote:
>> So I plugged the drives in and started exploring (they're 2 x 200 GB 
>> Maxtor
>> SATA disks). After many attempts I now have a new WinXP installation 
>> on the
>> new RAID-0 set, and all looks fine there. But after innumerable 
>> attempts and
>> much hair tearing I still have no trace of Gentoo. I've eventually
>> discovered that I need to pass "dmraid=X" to the installer at CD-boot 
>> time,
>> but the instructions are both wrong and unhelpful in telling me what X 
>> is. I
>> did manage to read "man dmraid" (though not print it - anyone know how to
>> print Linux man pages on a Windows box?) from which it seemed I needed an
>> -ay paramter, thus:
> 
> After quite a few experience with most software RAID that require 
> drivers I have come to the conclusion that they are not worth anything. 
> You are much better off using Linux software raid which will work even 
> if you change chipsets, as in upgrading your computer in a later point 
> in time.
> Also there are quite a few software Raid out there that require you to 
> rebuild the Raid if you ever update the Bios.
> 
> I would only use only actual real Hardware RAID such as an IBM ServeRaid 
> card.
> 
> If you need raid in Windows XP I think that it also supports a virtual 
> Raid system, I have never used it so ymmv.


Now here is a thing, is it possible to build gentoo form the ground up 
on a software RAID config.. i am pondering purchasing a gentoo server, 
but i figure theres no point is it won't play from the word go.

I want to use software raid 1 and LVM together, is this doable ? anyone 
have pointers or a website for me to look on ?

TIA

Neil
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Re: [gentoo-amd64] How to install to a RAID set?

[Mike Williams]

On Saturday 06 May 2006 21:47, Neil Stone wrote:
> Now here is a thing, is it possible to build gentoo form the ground up
> on a software RAID config.. i am pondering purchasing a gentoo server,
> but i figure theres no point is it won't play from the word go.

Yes.
If you're going for a simple mirror, then you can convert from a single disk 
easily.

> I want to use software raid 1 and LVM together, is this doable ? anyone
> have pointers or a website for me to look on ?

Yes.
Software raid makes block devices. LVM works on block devices.

-- 
Mike Williams
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[gentoo-amd64] Re: How to install to a RAID set?

[Duncan]

Nuitari posted <Pine.LNX.4.64.0605061613320.2752@melchior.nuitari.net>,
excerpted below,  on Sat, 06 May 2006 16:18:05 -0400:

> After quite a few experience with most software RAID that require drivers
> I have come to the conclusion that they are not worth anything. You are
> much better off using Linux software raid which will work even if you
> change chipsets, as in upgrading your computer in a later point in time.
> Also there are quite a few software Raid out there that require you to
> rebuild the Raid if you ever update the Bios.

That has been my conclusion as well.  I'm /extremely/ happy with my
quad-SATA Linux kernel based RAID setup.  One of the benefits is that one
doesn't have to choose a single RAID type for the entire disk set.  I'm
also counting on the fact that I can switch the SATA controller to
any chipset I want at any time, or upgrade BIOS, or anything else, without
having to rebuild the raid.

The layout here:

* A small RAID-1 for /boot.  Set up correctly, one can boot from any of
the drives in the RAID-1.  I have four drives, and I can set the BIOS to
boot from any of the four.

* A large partitioned RAID-6, for two-way redundancy, yet it's still
two-way striped as well.  The first partition is root (incl. /usr and
/var, thereby keeping the portage database in sync with what's actually on
the partitions), the second rootbak, a snapshot of root copied off
periodically, allowing me to boot to it in the event the main root won't
boot, for some reason.  I can also boot to it for recovery if portage
breaks on my main root.  It's identically sized to root, and likewise
includes its own synced /usr and /var/db/portage, tho of course root and
rootbak aren't in sync with each other except at the moment I've just
finished a backup snapshot.

Note the choice of partitioned RAID, rather than LVM, for root and
rootbak.  That's deliberate, as Linux kernel RAID is just that --
in-kernel, while LVM requires some userland help.  That means if I used
LVM for root, I'd have to hassle an initramfs (formerly initrd), something
I can avoid by putting root (and rootbak) on partitioned RAID.  The kernel
is loaded by GRUB from any of the /boot RAID-1 images, and the kernel is
all that's required to load /root, as it has everything built-in that  it
would need.

* A third partition on that RAID-6, bigger than the root and rootbak
partitions, used with LVM.  The LVM logical volumes on this partition
contain /home and homebak, /usr/local and a backup, /var/log with no
backup, mail and news partitions with a backup for mail, not news, my
media partition and its backup, the  portage packages dir (I use
FEATURES=buildpkg) and its backup, etc.

* A partitioned RAID-0 with two partitions, /tmp on one, and a second
partition containing the portage tree, the ccache cache, and the kernel
tree (symlinked from /usr/src), each in its own subdir.  Note that all of
these benefit very highly from the RAID-0, while not needing any
redundancy as they are easily redownloaded or rebuild.

With this setup, I have about the best mix possible, easy booting with no
serious complications, redundancy both in RAID and in snapshot backup
where I need it, and no hardware lockin -- I can replace two of the four
drives at once without losing anything but the throw-away data on the
RAID-0, and can switch out SATA chipsets and/or motherboard without losing
anything, either.  It's a combination no hardware RAID could ever match.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman in
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html


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Re: [gentoo-amd64] How to install to a RAID set?

[Boyd Stephen Smith Jr.]

[-- Attachment #1: Type: text/plain, Size: 2263 bytes --]

On Saturday 06 May 2006 15:47, Neil Stone <neil@flashtek-uk.com> wrote 
about 'Re: [gentoo-amd64] How to install to a RAID set?':
> Now here is a thing, is it possible to build gentoo form the ground up
> on a software RAID config.. i am pondering purchasing a gentoo server,
> but i figure theres no point is it won't play from the word go.

There's two types of SW RAID in the kernel.  One is standard, pure 
software, md-raid which can be maintained using raidtools (old and busted) 
or mdadm (new hotness).  I'm using this to run RAID 0 across two raptors.  
Upsides include ease of configuration and hardware independence.  
Downsides include (in practice) OS (Linux) dependence.

Then, there is the "firmware" raid.  The raid configuration is stored in 
hardware but all the actual /work/ is done in software.  Downsides include 
difficultly configuring, hardware dependence, and generally flakey 
implementation -- on both the firmware and Linux sides.  Upsides include 
(some) OS-independence.

Both are supported by Gentoo, but like most things Gentoo you will need to 
get in and configure stuff yourself, mostly using the tools provided by 
upstream.  While I know my way around mdadm and lvm fairly well and could 
help you there (they are simple tools anyway), I wouldn't be able to 
troubleshoot issues with dmraid or raidtools.

> I want to use software raid 1 and LVM together, is this doable ? anyone
> have pointers or a website for me to look on ?

Absolutely possible.  Use mdadm to create your RAID 1 block device 
(generally /dev/mdX) and then run pvcreate against that block device.  At 
this point all your standard LVM tools work like normal.

So that everything falls into place on boot, make sure your LVM 
configuration scans md devices for pvs (the default configuration does) 
and that mdadm attempts to recreate the device node on boot by adding a 
line like:
ARRAY /dev/md0 level=raid1 num-devices=2 
UUID=b64934c5:85356513:9b13d76e:c0280a56
to your /etc/mdadm.conf

-- 
"If there's one thing we've established over the years,
it's that the vast majority of our users don't have the slightest
clue what's best for them in terms of package stability."
-- Gentoo Developer Ciaran McCreesh

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Re: [gentoo-amd64] How to install to a RAID set?

[Robert Walter]

On Saturday 06 May 2006 22:18, Peter Humphrey wrote:
> Can anyone here help out? Even knowing the format of the name dmraid expects
> for an existing array would help, but I can't find anything anywhere.

i had the same problem like you. dualboot gentoo & xp on a software raid chipset. (nforce4 in my case)
unfortunately i didn't log all the steps needed to set it up :-( , 
but i can give you my modified scripts (written by gerte hoogewerf) and all the info i have to create an initrd if you want to give it a try. 
that ram disk "initializes" the raid files in /dev/mapper/*, before it is mounted 
sorry, i don't have all in mind right now. i have to replay the installation steps first.
some basic things i still know. you need
- dmraid-1.0.0.rc9 (or what is current now) and busybox
  use that together with gertes scripts to create the initrd
- initial ram disk and device mapper support in kernel
- your grub.conf needs an entry like
  title Gentoo Linux 2.6.15-r1 (reiser4, +marvel 1gbit ethernet)
  root (hd0,0)
  kernel /kernel-2.6.15-reiser4-r1 root=/dev/ram0 init=/linuxrc real_root=/dev/mapper/nvidia_eabdggea2 dodmraid vga=0x317 splash=0
  initrd (hd0,0)/initramfs
that should do it (more or less ;-) )
best regards robert

ps. there is no xp anymore on the box, but the nvraid is still on without any problems (although most of the partitions are reiser4!)
like all the other guys suggested, just use it if you want that raid used on a m$ os. go the linux way otherwise.

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Re: [gentoo-amd64] How to install to a RAID set?

[Peter Humphrey]

Ok, many thanks to all who replied.  I think I'll go the hardware route.

I've found a card that seems ideal for my needs: one that will fit into the
32-bit PCI 2.2 slots on this motherboard but doesn't cost more than the pair
of disks it will drive. It's the Adaptec 1210SA controller.

I'll go searching the HCLs, but meanwhile does anyone here have a view on
this device?

--
Rgds
Peter.



--------- Original Message --------
From: gentoo-amd64@lists.gentoo.org
To: gentoo-amd64@lists.gentoo.org <gentoo-amd64@lists.gentoo.org>
Subject: Re: [gentoo-amd64] How to install to a RAID set?
Date: 06/05/06 20:22

>
> &gt; So I plugged the drives in and started exploring (they're 2 x 200 GB
Maxtor
> &gt; SATA disks). After many attempts I now have a new WinXP installation
on the
> &gt; new RAID-0 set, and all looks fine there. But after innumerable
attempts and
> &gt; much hair tearing I still have no trace of Gentoo. I've eventually
> &gt; discovered that I need to pass &quot;dmraid=X&quot; to the installer
at CD-boot time,
> &gt; but the instructions are both wrong and unhelpful in telling me what
X is. I
> &gt; did manage to read &quot;man dmraid&quot; (though not print it -
anyone know how to
> &gt; print Linux man pages on a Windows box?) from which it seemed I
needed an
> &gt; -ay paramter, thus:
>
> After quite a few experience with most software RAID that require drivers
> I have come to the conclusion that they are not worth anything. You are
> much better off using Linux software raid which will work even if you
> change chipsets, as in upgrading your computer in a later point in time.
> Also there are quite a few software Raid out there that require you to
> rebuild the Raid if you ever update the Bios.
>
> I would only use only actual real Hardware RAID such as an IBM ServeRaid
> card.
>
> If you need raid in Windows XP I think that it also supports a virtual
> Raid system, I have never used it so ymmv.
> --
> gentoo-amd64@gentoo.org mailing list
>
>
>
>
>
>
>

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Re: [gentoo-amd64] How to install to a RAID set?

[Boyd Stephen Smith Jr.]

[-- Attachment #1: Type: text/plain, Size: 872 bytes --]

On Sunday 07 May 2006 06:06, "Peter Humphrey" <prh@gotadsl.co.uk> wrote 
about 'Re: [gentoo-amd64] How to install to a RAID set?':
> I've found a card that seems ideal for my needs: one that will fit into
> the 32-bit PCI 2.2 slots on this motherboard but doesn't cost more than
> the pair of disks it will drive. It's the Adaptec 1210SA controller.

Hrm. IIRC That's not a real HW RAID card.  It /might/ have some frimware 
RAID, but I don't think so.  Be careful, there's a lot of cards out there 
that claim HW RAID but really have firmware raid.

PS
A: Because it reverses the flow of conversation.
Q: Why shouldn't I top-post?

-- 
"If there's one thing we've established over the years,
it's that the vast majority of our users don't have the slightest
clue what's best for them in terms of package stability."
-- Gentoo Developer Ciaran McCreesh

[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]

Re: [gentoo-amd64] How to install to a RAID set?

[Etaoin Shrdlu]

On Saturday 06 May 2006 22:18, Peter Humphrey wrote:

> dmraid" (though not print it - anyone know how to print Linux man
> pages on a Windows box?)

I had to do this recently:

man dmraid | col -b > dmraid.txt

(use the actual man page name, of course)

This creates a txt file that you can open (and print as well of course) 
from windows.

HTH
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Re: [gentoo-amd64] How to install to a RAID set?

[Etaoin Shrdlu]

On Sunday 07 May 2006 13:06, Peter Humphrey wrote:
> Ok, many thanks to all who replied.  I think I'll go the hardware
> route.
>
> I've found a card that seems ideal for my needs: one that will fit
> into the 32-bit PCI 2.2 slots on this motherboard but doesn't cost
> more than the pair of disks it will drive. It's the Adaptec 1210SA
> controller.
>
> I'll go searching the HCLs, but meanwhile does anyone here have a view
> on this device?

Some pointers about what manufacturers/boards provide true hardware raid:

http://linuxmafia.com/faq/Hardware/sata.html
http://linux-ata.org/faq-sata-raid.html

I had to face this problem myself some time ago. Seems that areca, 3ware, 
IBM, some of Adaptec's and a few others are the ones you can choose from 
(they provide true hw raid). I bought an Areca ARC-1120 and I'm happy 
with it, but YMMV.
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Re: [gentoo-amd64] How to install to a RAID set?

[Nicolas MASSÉ]

[-- Attachment #1: Type: text/plain, Size: 715 bytes --]

On Sunday 07 May 2006 18:23, Etaoin Shrdlu wrote:
> On Saturday 06 May 2006 22:18, Peter Humphrey wrote:
> > dmraid" (though not print it - anyone know how to print Linux man
> > pages on a Windows box?)
>
> I had to do this recently:
>
> man dmraid | col -b > dmraid.txt
>
> (use the actual man page name, of course)
>
> This creates a txt file that you can open (and print as well of course)
> from windows.

I didn't know this tip, here is mine :

man -t dmraid > dmraid.ps
ps2pdf dmraid.ps

Hopping it will help,

-- 
Nicolas MASSÉ
Pour récupérer ma clef GPG:
gpg --keyserver wwwkeys.eu.pgp.net --recv-keys 0x2A18C433
Key fingerprint: 6621 FC23 5DC7 54BA B952 316A 50B1 BC3F 2A18 C433

[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]

Re: [gentoo-amd64] How to install to a RAID set?

[Peter Humphrey]

> Some pointers about what manufacturers/boards provide true hardware raid:
>
> http://linuxmafia.com/faq/Hardware/sata.html
> http://linux-ata.org/faq-sata-raid.html
>
> I had to face this problem myself some time ago. Seems that areca, 3ware,
> IBM, some of Adaptec's and a few others are the ones you can choose from
> (they provide true hw raid). I bought an Areca ARC-1120 and I'm happy
> with it, but YMMV.

Very useful - thanks. Looks like I'll have to try harder with sw raid, as I
don't think it's worth spending £300 to make the disks go faster, and this
box has only 32-bit PCI slots so I can't fit a modern card (unless you know
different).

--
Rgds
Peter.


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Re: [gentoo-amd64] How to install to a RAID set?

[Etaoin Shrdlu]

On Tuesday 09 May 2006 15:15, Peter Humphrey wrote:

> Very useful - thanks. Looks like I'll have to try harder with sw raid,
> as I don't think it's worth spending £300 to make the disks go faster,
> and this box has only 32-bit PCI slots so I can't fit a modern card
> (unless you know different).

I also have got a box running plain in-kernel software raid level 1 (with 
2x80GB EIDE disks), and I'm very happy with it also. I manage it with 
mdadm, and, after the initial setup and the mandatory tests (simulated 
failure, etc.) it runs very smoothly and you can really forget about it. 
Just follow the directions in the software-raid howto. If you want to 
have your / on a software raid, things are a little more complex (but 
not too much).
If you have many more reads than writes on your raid array, eg in a web 
server, software raid (expecially level 1 and 5) usually performs very 
well, since partial reads are performed in parallel (if you set up 
things carefully).
IIRC you have only two disks, so raid 1 or 0 are your only choices (be 
sure to backup regularly if you use plain raid 0 since it has no 
redundancy).


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Re: [gentoo-amd64] How to install to a RAID set?

[Mike Doty]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Peter Humphrey wrote:
> Well, here's a pretty kettle of fish, and no mistake.
> 
> Having had this dual-Opteron box for over two years with just plain IDE
> disks, I decided it was time to bite the bullet and plug in a couple of
> SATAs. So I did. The motherboard has a VIA chipset with what turns out to be
> firmware RAID, though I had thought in my innocence that anything in the
> chipset would be hardware
[snip]

Be very careful with that "raid" controller.  if there was a "raid"
array setup and the discs that you plugged in don't match what the
controller thinks then it ends up killing your partition tables if you
try to delete the old data.

- --
=======================================================
Mike Doty                           kingtaco@gentoo.org
Gentoo/AMD64 Strategic Lead         PGP Key: 0xA797C7A7
Gentoo Developer Relations
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Re: [gentoo-amd64] How to install to a RAID set?

[Mike Doty]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Boyd Stephen Smith Jr. wrote:
> On Sunday 07 May 2006 06:06, "Peter Humphrey" <prh@gotadsl.co.uk> wrote 
> about 'Re: [gentoo-amd64] How to install to a RAID set?':
>> I've found a card that seems ideal for my needs: one that will fit into
>> the 32-bit PCI 2.2 slots on this motherboard but doesn't cost more than
>> the pair of disks it will drive. It's the Adaptec 1210SA controller.
> 
> Hrm. IIRC That's not a real HW RAID card.  It /might/ have some frimware 
> RAID, but I don't think so.  Be careful, there's a lot of cards out there 
> that claim HW RAID but really have firmware raid.
iirc it's a fakeraid card

- --
=======================================================
Mike Doty                           kingtaco@gentoo.org
Gentoo/AMD64 Strategic Lead         PGP Key: 0xA797C7A7
Gentoo Developer Relations
                 ===GPG Fingerprint===
   0094 7F06 913E 78D6 F1BB  06BA D0AD D125 A797 C7A7
=======================================================
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Re: [gentoo-amd64] How to install to a RAID set?

[Peter Humphrey]

I've just found this one.

On Sunday 07 May 2006 13:31, Boyd Stephen Smith Jr. wrote:

> A: Because it reverses the flow of conversation.
> Q: Why shouldn't I top-post?

Regular readers (TM) will know that I'm not usually guilty of this. However, 
while I'm fighting this box to get Gentoo installed on firmware RAID I 
sometimes don't have a proper system available with MUA etc. That e-mail of 
mine came from a Windows system reading mail via my ISP's web-mail system, 
in which proper formatting is hard to achieve.

I won't do it any more than I can help.

-- 
Rgds
Peter.
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Re: [gentoo-amd64] How to install to a RAID set?

[Peter Humphrey]

On Sunday 07 May 2006 02:40, Robert Walter wrote:

> i had the same problem like you. dualboot gentoo & xp on a software raid
> chipset. (nforce4 in my case) unfortunately i didn't log all the steps
> needed to set it up :-( , but i can give you my modified scripts (written
> by gerte hoogewerf) and all the info i have to create an initrd if you
> want to give it a try. that ram disk "initializes" the raid files in
> /dev/mapper/*, before it is mounted sorry, i don't have all in mind right
> now. i have to replay the installation steps first. some basic things i
> still know. you need

...etc

Well, I tried the Software-RAID-HOWTO, and used a SuSE 9.3 DVD I had lying 
around to create /dev/md0 to /dev/md5 on the /dev/sd[ab] disks that are 
attached to the SATA interface. SuSE installed just fine and is happy to 
run on these devices.

In spite of that, when I boot the Gentoo 2006.0 installation CD and tell it:

   gentoo dodmraid dmraid=-ay

It says in the boot sequence:

   Activating Device-Mapper RAID(s)
   No RAID disks

Then when the image has booted, I say  fdisk -l and I see the partitions 
on /dev/sda and /dev/sdb with no trace of /dev/mdX.

What am I doing wrong?

Meanwhile I'll have a play with your scripts, Robert, and see if that gets 
me anywhere - thanks.

-- 
Rgds
Peter.
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Re: [gentoo-amd64] How to install to a RAID set?

[Etaoin Shrdlu]

On Wednesday 17 May 2006 12:47, Peter Humphrey wrote:

> Well, I tried the Software-RAID-HOWTO, and used a SuSE 9.3 DVD I had
> lying around to create /dev/md0 to /dev/md5 on the /dev/sd[ab] disks
> that are attached to the SATA interface. SuSE installed just fine and
> is happy to run on these devices.
>
> In spite of that, when I boot the Gentoo 2006.0 installation CD and
> tell it:
>
>    gentoo dodmraid dmraid=-ay
>
> It says in the boot sequence:
>
>    Activating Device-Mapper RAID(s)
>    No RAID disks
>
> Then when the image has booted, I say  fdisk -l and I see the
> partitions on /dev/sda and /dev/sdb with no trace of /dev/mdX.
>
> What am I doing wrong?
>
> Meanwhile I'll have a play with your scripts, Robert, and see if that
> gets me anywhere - thanks.

This used to confuse me as well - from what I understand, MD raid (the 
one you set up with SuSE) and DM raid (the one you are trying to use 
with gentoo) are very different beasts. MD raid is the classic plain 
software raid (the one you set up using the software-raid howto), while 
DM raid (aka ataraid, biosraid, bios-assisted raid, and other similar 
names) uses the device mapper and is used mainly to be able to use raid 
volumes (often created under windows) that lie on disks attached to 
firmware-raid cards. 
These cards come with drivers (usually windows-only and proprietary) that 
emulate a hw-raid, so that windows can see the array as a single drive. 
Nevertheless, it's still an emulated (in software+firmware) hw-raid, 
meaning that a real os (like linux) will see the single physical drives, 
unless some kind of workaround (like DMraid) is in place, and even then 
I would not put my valuable data on it. That's why I (and others as 
well) suggest using plain MD software raid.

See here:
http://people.redhat.com/~heinzm/sw/dmraid/readme

and, for the gentoo part
http://tienstra4.flatnet.tudelft.nl/~gerte/gen2dmraid/
(read the "What can I do with the LiveCD / dmraid?" section)

Hope this helps.
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Re: [gentoo-amd64] How to install to a RAID set?

[Boyd Stephen Smith Jr.]

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On Wednesday 17 May 2006 05:47, Peter Humphrey <prh@gotadsl.co.uk> wrote 
about 'Re: [gentoo-amd64] How to install to a RAID set?':
> Well, I tried the Software-RAID-HOWTO, and used a SuSE 9.3 DVD I had
> lying around to create /dev/md0 to /dev/md5 on the /dev/sd[ab] disks
> that are attached to the SATA interface. SuSE installed just fine and is
> happy to run on these devices.

Ah, very good, you are using pure software raid.  Did you use raidtools or 
mdadm to create these devices?

> In spite of that, when I boot the Gentoo 2006.0 installation CD and tell
> it:
>
>    gentoo dodmraid dmraid=-ay

You don't need either of those options.  dmraid is "firmware" raid, nor 
pure software raid.

> It says in the boot sequence:
>
>    Activating Device-Mapper RAID(s)
>    No RAID disks

Sounds normal, since you didn't say you created any dmraid devices.

> Then when the image has booted, I say  fdisk -l and I see the partitions
> on /dev/sda and /dev/sdb with no trace of /dev/mdX.
>
> What am I doing wrong?

Probably nothing.  If you used the (old, busted) raidtools way of creating 
the md devices, there's no metadata on the devices themselves that tells 
Gentoo the devices are part of a raidset.  So, there's no way for Gentoo 
to create the /dev/mdX devices automatically.  You should be able to grab 
your raidtab from your SuSE initrd/initramfs or / partition and activate 
the devices your self though.

If you used the (new, hotness) mdadm way of creating the devices, well, 
Gentoo probably /should/ have automatically created the devices.  You 
might want to file a bug.  In the meantime, the booted image should 
contain mdadm and you should be able to use the "scan" and "assemble" (?) 
options to create your devices.

-- 
"If there's one thing we've established over the years,
it's that the vast majority of our users don't have the slightest
clue what's best for them in terms of package stability."
-- Gentoo Developer Ciaran McCreesh

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Re: [gentoo-amd64] How to install to a RAID set?

[Peter Humphrey]

On Wednesday 17 May 2006 11:47, Peter Humphrey wrote:

[...pleas...]

Thanks to those who helped. I now have a system running on software RAID on 
my new SATA disks.

-- 
Rgds
Peter.
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[gentoo-amd64] Re: How to install to a RAID set?

[Duncan]

Peter Humphrey <prh@gotadsl.co.uk> posted
200605271156.05251.prh@gotadsl.co.uk, excerpted below, on  Sat, 27 May
2006 11:56:05 +0100:

> Thanks to those who helped. I now have a system running on software RAID on 
> my new SATA disks.

Very cool! =8^)  Thanks for the update!

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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