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-   -   nForce2 motherboards, SATA disks and SATA RAID under Linux (http://www.nvnews.net/vbulletin/showthread.php?t=50663)

radezz 05-15-05 04:31 PM

nForce2 motherboards, SATA disks and SATA RAID under Linux
 
Hello,

Can someone point me to more information (if anyone had organized it in one place on the net) about these things: nForce2 mobos, SATA disks (I gave up on the mo-bo RAID on my GA7N400S-L and tried to set up the mdadm software RAID) and RAID under Linux.

Here is my experience, I hope it will help someone, but I am still looking for solution for my problems. I am not looking for exact answers here, but if someone knows more about it, feel free to let me know more about these things/problems:

- I tried installing the Debian "testing" (sarge) version (because it has newer packages and is almost ready to be released as the official stable one), and the first thing I learned was that the disk driver for SATA disks on the kernel included with sarge (2.6.8) is not good. You have to compile your own kernel because the "nv_sata" module was fixed in 2.6.9, or you can download a pre-compiled kernel and live with the fact that someone else decided which modules to be compiled in the kernel and which to be left as kernel modules.

- I compiled my own 2.6.11 kernel but that didn't help me fix the problems.

- the only way to make kernel see my SATA disks was to actually disable them in BIOS - yes to say that they weren't there, and then my kernel saw them, recognized them and started working with them (I can't remember if this was with 2.6.8 or 2.6.11)

- a good solution for the Linux RAID - moving the system to be booted from that technology is at http://psilocybe.update.uu.se/~jonas...x.pl/linuxraid - a gread howto, but after I finished with that, my configuration can only see the first RAID I created there (md0) but I partitioned the SATA disks into several partitions, and at some point I manually created md1 and md2, but I can't see them no longer.

- when I try fdisk -l, no matter what I tried with the boot parameters for the LILO (e.g. append="hda=noprobe..." etc. ) the system only sees the md0.

- another strange thing is that now I have /dev/sda, /dev/sdb and /dev/sdc, and b and c are the actual drives, and /dev/sda is a phantom drive with only 8 megabytes size; when I read the docs of my SEAGATE SATA disks I discovered they had 8mb cache on them - so it seems that I can see one cache as the sda disk...

- the performance of the md0 is not bad - hdparm -t shows excellent results, much better than the IDE disk I had connected as /dev/hda (while it was visible).

Anyway, here it is, all impressions/information piled up, if someone knows more about these things, please share it with me, and if someone wants to play with these things, you may experience these problems.

Best regards,
Rade

denbert 11-06-06 02:19 PM

Re: nForce2 motherboards, SATA disks and SATA RAID under Linux
 
Hi,

Just installed SME Server 7.0 based on CentOS 4.3, and now I’m stuck….

Installing the server in Hardware Raid1 runs fine, but after reboot, the server hangs in GRUB!

Anyone got a solution on this.

The mobo is MSI K7N2-Delta2 Platinum.

Cheers

kenyee 11-07-06 10:00 AM

Re: nForce2 motherboards, SATA disks and SATA RAID under Linux
 
Reinstall w/ mdadm.
Look up "fakeraid" to see what this "hardware" raid is. It's a waste of time...don't bother with it. There's a reason real hardware RAID solutions cost $200-300 more...

fhj52 11-19-06 04:08 AM

Re: nForce2 motherboards, SATA disks and SATA RAID under Linux
 
Quote:

Originally Posted by kenyee
Reinstall w/ mdadm.
Look up "fakeraid" to see what this "hardware" raid is. It's a waste of time...don't bother with it. There's a reason real hardware RAID solutions cost $200-300 more...

And that reason is that RAID card manufacturers want to take every dime you have. ;)

There was a time when the ''real'' RAID was the only ''real'' solution. Not so anymore.
The performance difference between software raid and hardware raid is so small that it is barely even noticeable on any modern(read: >2GHz) workstation/server(read: multi-processor) system under normal workloads/conditions.
( Of course, that changes when concurrent access goes into hundreds-thousands and/or file sizes are > total system memory. )
...
You can run your tests but I ran mine and the results are very clear. NVRAID does just fine for normal workstation usage. I'd be a lot happier if it had a stripe of mirrors(1+0) rather than mirror of stripes(0+1) for what they mislabeled as RAID 10 but it still provides fault tolerance.

fhj52 11-19-06 04:51 AM

Re: nForce2 motherboards, SATA disks and SATA RAID under Linux
 
@Rade

I think you should get/use, at the very least, kernel 2.6.16 but I suggest 2.6.18.
I understand the reasons about using ancient kernels but you cannot do that and have modern hardware. Linux just does not work that way. Debian et al can only backport so much functionality...

NVRAID has to be setup in Linux using the device-mapper modules, aka ''dmraid'' as it is known. NVRAID 0, 1 & 0+1 have been supported for a while. The NVRAID 5 is supported but still not so easy. It is very new so it may not work... pretty complicated to setup too. I have not made it work yet.
Also, dmraid is not supported at boot by most distros so you cannot have any drives with NVRAID available until after the OS boots. YOU can make an initrd that will allow it but again, a little difficult.

I've been running NVRAID 0+1 for a few months using dmraid. No big problems and performance is okay/good considering the drives are (S)ATA.
There is some kind of issue with performance on files that are much greater than the total system memory... don't know why but that would rarely affect anybody. (Only hard core number crunchers, finite element analysis, copying/moving DVD images, etc.)

If you are not booting to MS OS & Linux or *BSD & Linux or whatever & Linux, perhaps it would be best to just use Linux SW raid. The multipath-device(md) modules work fine and the level of difficulty for setup is not too bad.
If you do need cross-OS compatibility, then NVRAID or an adapter card is the only way to go. You will need a recent kernel _and_ modules for that.
...
Good Luck!

Edit:
I forgot I had these links that might help you.
Linux Software RAID: http://www.sanitarium.net/golug/Linu...ware_RAID.html
Storage Review's reprint of PC Guide's old RAID guide: http://www.storagereview.com/guide20...aid/index.html
( It still has valuable information about RAID even though quite a bit dated in some areas. )


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