Dual-boot on SATA RAID 0 [SOLVED]

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Hello all,

Now that I have one of my computers completely how I want it, it's time to work on the others, which all use SATA RAID 0. What I want to do is install Windows XP and Gentoo on the RAID. I'm thinking that I know how to do this task, but before I start, I'd like to make sure. I believe the steps should be:

1. Install Window$ on the primary partition of the primary drive (sda & hd0,0 in GRUB)
2. Boot the minimal install CD
3. Create partitions 2, 3, and 4 to use as the Gentoo partitions
4. Install Gentoo
5. Setup GRUB with all the necessary parts for booting both operating systems.

That all makes sense to me, but I am wondering about a few things.

1. Does GRUB use sd0,0 in accordance with Gentoo using sda, or does it still refer to the partitions as hd0,0 et cetera?
2. Is there a way to make a partition that will hold files that can be used by both Windows and Gentoo (namely my roughly 40GB of music)?
3. I know that I load in the RAID driver for Windows, but is there a particular driver for Gentoo that needs to be loaded in my kernel?

Thanks a bunch for your help.
--Zach
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“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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IQgryn · l33t Joined: 05 Sep 2005 Posts: 764 Location: WI, USA

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Questions 1 and 3 (yes, it is a hardware RAID) are totally cleared up; thank you so much! However, I'm still a little curious about number 2. Would this partitioning scheme work?:

/dev/sda1 --> Windows --> about 80GB (ntfs)
/dev/sda2 --> Boot --> 32MB (ext2)
/dev/sda3 --> Swap --> 512MB (swap)
/dev/sda4 --> Root --> about 80GB (ext3)
/dev/sda5 --> BOTH OS --> remainder of HDD space (ntfs-3g)

How does Windows recognize/access this partition?
How does Gentoo?
How does one setup the ntfs-3g filesystem (sorry, I'm not familiar with it)?

Thanks so much!

--Zach
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“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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IQgryn · l33t Joined: 05 Sep 2005 Posts: 764 Location: WI, USA

Ntfs-3g is the new NTFS driver for Linux. It works with a standard NTFS partition, and enables safe read and write support via FUSE. You'll need to enable FUSE in your kernel, and install ntfs-3g from portage. See http://www.ntfs-3g.org/ for more information about ntfs-3g. You could set up the filesystem with Windows or by using mkfs.ntfs from Linux.

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Thanks, I'm going to work on this dual-boot tomorrow. If I run into any problems or have more questions, I'll post them. It's awesome to know that there are tons of people willing to help.

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“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

I think for now I'm going to just setup two separate operating systems with no partition to share between the two. I just don't know about the stability of the ntfs-3g driver. Maybe sometime down the road I will try it out, but for now, I have the HDD space to do separate partitions.

Thanks for all the help.

--Zach
_________________
“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

When starting the minimal installation CD for x86, it detects the two SATA HDDs that I have as /dev/sda and /dev/sdb. What will I need to do with fdisk since it is a RAID 0? I noticed that when I just type fdisk without any options, it says the following at the end:

cyrillic · Posted: Fri Mar 23, 2007 3:36 pm Post subject:

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

My machine uses the Promise SATA RAID controller that's on my ASUS P4P800E-Deluxe motherboard. I assumed that meant it was a hardware RAID, but I was also under the impression that there were only two types: hardware and software. Is there a guide or anything that I can look at for my situation? Is it a terribly different/difficult compared to my other computers which are AMD64 with 1 PATA drive for one OS and 1 PATA drive for Gentoo (not RAID)?

Thanks,
Zach
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“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Has anyone done this type of installation? I've looked around and it doesn't seem like there is a particular guide. I found the one for software RAID, but that's not what I have. I'd really like to get Gentoo installed on that computer as well.

Thanks.
_________________
“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

I decided to just use the two SATA drives as individuals, instead of in RAID. Thanks anyway.
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Bones McCracker · Veteran Joined: 14 Mar 2006 Posts: 1611 Location: U.S.A.

I suggest you search for threads that discuss dmraid.

I haven't done this on Gentoo, but I've done it multiple times on other distros. Hopefully somebody will chime in with the precise procedure for Gentoo. But the advice I give you below might suggest a few keywords you can use to better research this issue -- it's been done by many people I'm sure.

First of all -- if you can avoid having Gentoo on the same array as your Windows is installed to, it will be substantially easier for you, as you will be able to use Linux soft raid and avoid having to deal with your fake raid card. I have never seen any evidence that the fake raid cards (i.e., bios raid, onboard raid, sataraid, etc.) give any performance advantage over soft raid as already provided by Linux. But if you want to dual-boot with a Windows install that's already striped on that array, you need (I believe) to stick with your fake raid while using linux as well.

And, if that's what you intend to do (dual-boot Linux and Windows both on the same fake raid array), and it's a striping array (i.e. raid 0 or other "multiple physical disks are one logical disk" configuration), then you probably require the use of dmraid.

This will map your multiple physical drives to a single device. You can then partition that device, install to it, and so on. You will need the dmraid driver while installing, and you will need to install it so your system will work. As I have used it in the past, it's a kernel module, but it might be available as a built-in kernel option that I'm not aware of (it's been a year since I did it).

So you probably need to do something similar to the following:
boot up install CD or liveCD
check to see if it's got dmraid support
get the module if it's not on the disk
load the module
map and partition the drives
install, including dmraid for the system itself to be able to use the array once your reboot it

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Thanks for the plethora of information. However, after researching the issue further, I found that RAID 0 on Linux really isn't that much of a performance boost. I rarely use Windows anyway, so I just decided to set it up as two separate SATA drives. Again, though, I really appreciate the information and will read it soon.

--Zach
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“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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Bones McCracker · Veteran Joined: 14 Mar 2006 Posts: 1611 Location: U.S.A.

Well, if you're not going to use the sataRAID on the Windows side, then that opens up an additional possibility.

Partition off half of each disk and use that as your RAID in Linux. Setting up soft RAID in Linux is easy.

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Is using the Linux softRAID really that big of a performance boost?
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“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
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Bones McCracker · Veteran Joined: 14 Mar 2006 Posts: 1611 Location: U.S.A.

I've never actually benchmarked it, but I got an easily noticeable improvement in file i/o on the system I used it on.

I didn't bother using it on another system because I assumed it would not achieve a performance gain on that system.

It depends on what your system's binding file i/o constraint is (i.e., what's the bottleneck on your particular system).

If implementing RAID allows you to achieve a parallel channel where a bottleneck currently exists, then it could double the speed of your disk I/O (depending on what next becomes the binding constraint).

If your single-channel disk I/O is not the current binding constraint, then you will achieve no performance gain. (I.e., if you have old cheap-ass disks, a crappy old controller card(s) suck, an old motherboard with an inadequate chipset, or a wimpy CPU, etc. -- any of these can be the bottleneck too).

What you REALLY ought to do is softRAID 1. But if you're looking to tweak all the speed you can out of your system, then give it a try.

The dmraid thing is not impossible to do. I've heard it's pretty easy on Gentoo. Although, when I did it on a Debian system about year and a half ago, it took me (a total noob at the time) a week of screwing around to get it to work (mostly screwing around with GRUB). Later, I ditched Windows on that machine and used Linux RAID, and it was just as fast. It was just that, having purchased an expensive ASUS-A8N-SLI-Premium partly because it had an SATA-II RAID controller built-in, I wanted to use it. I didn't really understand at that time that the "SATA RAID Controller card" of that type relies upon the CPU to do it's work anyway -- it's just a remapper.

You also have to keep in mind that everybody in any forum of this type is basically a "shit-house lawyer". You will get a lot of advice that's just plain wrong. Always try to consult multiple sources. When somebody makes a blanket statement like, "Linux RAID doesn't offer much of a performance gain", I question that. It, like the fakeRAID cards, will not offer the performance gain of an expensive add-in RAID card that carries the RAID workload itself. But if your system is currently waiting on disk i/o, it sure as hell will offer SOME performance gain.

NathanZachary · Moderator Joined: 30 Jan 2007 Posts: 2605

Thanks again for offering more than one perspective. I, like you, don't take one opinion as the be-all-end-all. I don't think that i/o is where I'm currently bottlenecking. Actually, the computer that I currently have Gentoo on seems to run fairly quickly. Given that, I would imagine that my other computer will run it even better because it has MUCH better components. For now, I'm going to stick to a normal installation (except this time on SATA instead of PATA HDDs). Maybe later I will try the softRAID 1.

Thanks again.
_________________
“Truth, like infinity, is to be forever approached but never reached.” --Jean Ayres (1972)
---avatar cropped from =AimanStudio---