Arch Linux

daneel971

Member

Registered: 2008-03-28

Posts: 197

hard disks order / swapped drives

PC with 3 sata hds:

sata1 200Gb
sata2 750Gb
sata3 750GB

The Arch installer says that the 200Gb disk (connected to the first sata controller: no doubt, I checked this carefully) is sdb instead of sda.
Proceed with the installation on sdb: all fine. Installing grub: the installer create for me a "root (hd1,0)" entry, according to what it thinks regarding my hard disks...
When I reboot, i get a "file not found" error from grub: grub sees my disk in the "right way" - the 200Gb drive is hd0, and fixing the entry allow me to boot (with "root=/dev/sdb1", anyway).
How come that grub and the kernel have different ideas about the hds order?
(BTW: with Fedora the order is the same; and the issue happens even on another PC - ASUS Mb both, if that matters...)

rayjgu3

Member

From: Chicago IL usa

Registered: 2004-07-04

Posts: 695

Re: hard disks order / swapped drives

so what drive gets sda?
is there any ide drives  or maybe scsi possibly usb?
the drive recognition order deppends on what gets loaded 1st
if in your hooks of installation drive sata is before ide scsi usb , then sata gets sda

daneel971

Member

Registered: 2008-03-28

Posts: 197

Re: hard disks order / swapped drives

The 750Gb drive connected to the sata2 controller gets sda.
No ide drives at all, nor usb/fw drives connected.
There are only 3 sata drives.

... fascinating, uh?

rayjgu3

Member

From: Chicago IL usa

Registered: 2004-07-04

Posts: 695

Re: hard disks order / swapped drives

The 750Gb drive connected to the sata2 controller gets sda.
No ide drives at all, nor usb/fw drives connected.
There are only 3 sata drives.

... fascinating, uh?

so other drives are sata while #2 is sata2?
is any of these on a controller card as opposed to motherboard?

daneel971

Member

Registered: 2008-03-28

Posts: 197

Re: hard disks order / swapped drives

Sorry, I should be more specific.
There's no additional controller: the three sata controller are all onboard. The two that are "swapped" are, as said, sata1 and sata2.
On another PC I have a similar setup with four sata disks, and even here Arch swap two of them while Fedora keeps them in place. Again, Grub agrees with Fedora regarding the hard disk order.
If hadn't paid attention while installing, in this case I had wiped out one of my partitions: I noticed during the install process that the size of the drives were different than I was expecting: sdb became sdc and vice versa (sda remained the same, though).

rayjgu3

Member

From: Chicago IL usa

Registered: 2004-07-04

Posts: 695

Re: hard disks order / swapped drives

only thing coming to mind is in your bios you probably have option to set which drive to boot from
it may be that it is set to sata2 drive other than sata1
if sata2 doesnt have mbr then it goes in order of mobo looking to sata1 then sata3

while installing arch ot may have looked in the bios seen sata2 was being pointed at first so it gave it sda then followed order of controller after that
while grub just seen the controlers & put them in order of controler #

just thoughts coming to mind

daneel971

Member

Registered: 2008-03-28

Posts: 197

Re: hard disks order / swapped drives

only thing coming to mind is in your bios you probably have option to set which drive to boot from
it may be that it is set to sata2 drive other than sata1

Grub uses the bios to guess the drive order, and grub recognize them in the "right" way. The boot sequence starts with sata1: the disk on the first port of the sata controller - hd0 for Grub. Once the boot starts, the Arch kernel takes place and swap the drives.
Apart from this, the system works flawlessy - as I suggested above, this could nonetheless lead to big mistake during the installation with other OSs.

hrikkengaa

Member

From: Netherlands

Registered: 2008-04-07

Posts: 11

Website

Re: hard disks order / swapped drives

I am experiencing the same problems. Anyone know a solution to this issue?

P.S. I have a Asus M3A motherboard (latest BIOS).

---

...one taco is never enough...

inz.mamon

Member

From: Poland

Registered: 2009-11-24

Posts: 4

Re: hard disks order / swapped drives

Hi,
as a solution, you should use "by-uuid" naming for your drives in /boot/grub/menu.lst file.
That's how mine looks like:

# boot sections follow
# each is implicitly numbered from 0 in the order of appearance below
#
# TIP: If you want a 1024x768 framebuffer, add "vga=773" to your kernel line.
#
#-*

# (0) Arch Linux
title  Arch Linux
root   (hd0,0)
kernel /vmlinuz26 root=/dev/disk/by-uuid/d383ef7d-4c0f-4cb8-a766-b2f4c9d380cb ro vga=773
initrd /kernel26.img

# (1) Arch Linux
title  Arch Linux Fallback
root   (hd0,0)
kernel /vmlinuz26 root=/dev/disk/by-uuid/d383ef7d-4c0f-4cb8-a766-b2f4c9d380cb ro
initrd /kernel26-fallback.img

# (2) Windows
#title Windows
#rootnoverify (hd0,0)
#makeactive
#chainloader +1

Of course, your drive's uuid will be different. How to get it?
Here's the hint:   http://wiki.archlinux.org/index.php/Per … ice_naming

Or you can do:

inzmamon ~ $ sudo blkid
Password: 
/dev/sda1: UUID="d9707bfc-708b-49b0-a68c-b346c752c0e7" TYPE="ext2" 
/dev/sda2: UUID="675b6205-9226-41e6-b8ea-1c5f7c0a6818" TYPE="swap" 
/dev/sda3: UUID="d383ef7d-4c0f-4cb8-a766-b2f4c9d380cb" TYPE="reiserfs" 
/dev/sdc1: UUID="812d79fb-6d02-4d3b-aef5-f71cba39022c" TYPE="reiserfs"

Same way of naming shoud be usen in /etc/fstab to avoid boot time problems.
To be honest - I don't know why GRUB recognizes drive names differently, but I had such problem on one of my servers.
Every couple of boot-ups system would initialize, but most of time there was an error "fsck check failed ...."

Good luck.

rusty99

Member

Registered: 2009-03-18

Posts: 253

Re: hard disks order / swapped drives

cough * 2008-04-19 18:29:52 * cough