Linux and Raid

[daniel49]

I have always run linux in the past on its own drive with grub written to the mbr of my windows install drive. (Pata...xp on master, linux on slave)

Recently I purchased 3 new sata drives and set them up in a raid(0) Installed xp on the array and it is functioning as It should be. I wiped the old xp drive and use it for backup only.
So at that point. I decided to redo my linux install.(I use pclinux but ocasionally look at others)
Ran the latest live cd and proceeded to do an fresh install.
As the installer checked my drives it came back with the error message for the array that it was corrupted and it could not use it.
This was fine since I was able to install linux to one of the older pata drives and that worked fine.

But my questions are: 1) The array is not corrupted (as I am using it without problems) so evidently linux or perhaps this distro is just unable to understand it in some way.
could I get a short explanation of this to understand linux and raid arrays better.

2) since linux was having a problem with the array, I chose to write grub to the linux drive instead of the windows drive as I usually would of. As I did not feel confident that attempting to write grub to a drive it was viewing as corrupted would be successful.
This still allows me to duel boot but is a little more inconvenient as I have to make a quick jump to the bios and change boot order to access that drive.
Was there a better route to accomplish what I wanted?
thx in advance

 

[Crusty]

Unless Linux has a driver for your specific RAID controller it's not going to be able to figure out what it is, and if it's onboard RAID the chances of that are slim.

 

[daniel49]

Originally posted by: Crusty
Unless Linux has a driver for your specific RAID controller it's not going to be able to figure out what it is, and if it's onboard RAID the chances of that are slim.

That makes sense since xp had the same basic problem before I supplied it with a floppy:-(

yes they are onbord controllers.
its a Abit kv8max3 mb

with 2 Serial ATA channels via VT8237 south bridge
and
4 Serial ATA channels via Sil3114 SATA RAID controller.
I am using the Sil 3114 controller.

 

[Crusty]

Well to make your boot process easier you can use your Linux drive as the MBR and use a chainloader in grub to boot Windows. That's how a pretty typical dual-boot is setup. It shouldn't matter that Windows is on an array. Y

Whenever I setup multi-boots I always install the oldest version of Windows first up until the most recent. That way when you're done you have a properly built windows boot loader on your disk/array that can boot any of the installed windows. Once that is all functioning I then install Linux choosing to write the MBR to it's own drive, and then tell the BIOS to boot from that drive.

I'm not familiar with PCLinux and whether or not it will create the right chainloader entry to get your Windows to boot, but it's a pretty easy addition and I believe the default menu.lst file has an example in the comments. I just checked and the latest Ubuntu uses a version of grub that uses a different configuration scheme then from what I remember so I can't be sure.

 

[Nothinman]

Unless Linux has a driver for your specific RAID controller it's not going to be able to figure out what it is, and if it's onboard RAID the chances of that are slim.

Actually there's dmraid which supports most onboard, software RAID controllers. It really depends on the chipset and the data format they use for their RAID info.

could I get a short explanation of this to understand linux and raid arrays better.

Onboard, software RAID arrays don't count. They're essentially a software driver and some magic glue for booting. Real hardware RAID just presents a single block device per-volume.

Was there a better route to accomplish what I wanted?

The other way probably would've worked fine unless there's a real hardware or driver problem.

 

[daniel49]

Originally posted by: Nothinman

Unless Linux has a driver for your specific RAID controller it's not going to be able to figure out what it is, and if it's onboard RAID the chances of that are slim.

Actually there's dmraid which supports most onboard, software RAID controllers. It really depends on the chipset and the data format they use for their RAID info.

could I get a short explanation of this to understand linux and raid arrays better.

Onboard, software RAID arrays don't count. They're essentially a software driver and some magic glue for booting. Real hardware RAID just presents a single block device per-volume.

Was there a better route to accomplish what I wanted?

The other way probably would've worked fine unless there's a real hardware or driver problem.

Not sure if I was too vague. but just to clarify for you I do not have a software raid array set up.
I have 3 identical hd's cabled to a raid controller and set it up using my MB's raid bios.
As I understand it from my reading thats a hardware raid array..correct me if I am mistaken :=) It wouldn't be the first time.

 

[Crusty]

Originally posted by: Nothinman

Unless Linux has a driver for your specific RAID controller it's not going to be able to figure out what it is, and if it's onboard RAID the chances of that are slim.

Actually there's dmraid which supports most onboard, software RAID controllers. It really depends on the chipset and the data format they use for their RAID info.

I was under the impression that dmraid was more likely to not work then work, but it's definitely worth taking a look at. Good idea

 

[Nothinman]

Not sure if I was too vague. but just to clarify for you I do not have a software raid array set up.
I have 3 identical hd's cabled to a raid controller and set it up using my MB's raid bios.
As I understand it from my reading thats a hardware raid array..correct me if I am mistaken :=) It wouldn't be the first time.

Onboard RAID is what I'm talking about when I was saying software RAID. The BIOS does a bit of work to make booting possible, but once your OS boots up the real work is done in the driver, i.e. in software. That's why so often when you go to install Linux on one of those arrays the installer sees X amount of disks instead of 1 array.

I was under the impression that dmraid was more likely to not work then work, but it's definitely worth taking a look at. Good idea

Well, I don't have any first hand experience since I only use those controllers as standard controllers with no RAID. Linux software RAID is so much better and more capable it's not even funny.

 

[Crusty]

Originally posted by: Nothinman

Not sure if I was too vague. but just to clarify for you I do not have a software raid array set up.
I have 3 identical hd's cabled to a raid controller and set it up using my MB's raid bios.
As I understand it from my reading thats a hardware raid array..correct me if I am mistaken :=) It wouldn't be the first time.

Onboard RAID is what I'm talking about when I was saying software RAID. The BIOS does a bit of work to make booting possible, but once your OS boots up the real work is done in the driver, i.e. in software. That's why so often when you go to install Linux on one of those arrays the installer sees X amount of disks instead of 1 array.

I was under the impression that dmraid was more likely to not work then work, but it's definitely worth taking a look at. Good idea

Well, I don't have any first hand experience since I only use those controllers as standard controllers with no RAID. Linux software RAID is so much better and more capable it's not even funny.

Completely agree here. I've never had any problems using mdraid, and I use it all over the place

 

[skyking]

^^^^ Love that mdraid!^^^^^
It's so easy I never build single disk machines any more.