How to do a gentoo install on a software RAID

[schism39401]

I have setup a raid1 on my workstation but cat /proc/mdstat shows this:

[als]

I have been looking all over these forums to try and install gentoo linux on my SATA (2) 80gb Hard Drives Raid 1. Im also using a PCIe (ATI x700) video card. Not sure if that makes a difference for this part. I have followed this guide step by step about 15 different times.


Here's my error. (When booting)
>> Loading modules
:: Scanning for .......
//
//
>> Activating udev
>> Determining root device...
!! The root block device is unspecified or not detected.
Please specify a device to boot, or "Shell" for a shell...



Fdisk /dev/sda

Device Boot Start End Blocks Id System
/dev/sda1 * 1 32 257008+ fd Linux raid autodetect
/dev/sda2 33 9451 75658117+ fd Linux raid autodetect
/dev/sda3 9452 9963 4112640 82 Linux swap / Solaris

Fdisk /dev/sdb

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 32 257008+ fd Linux raid autodetect
/dev/sdb2 33 9451 75658117+ fd Linux raid autodetect
/dev/sdb3 9452 9963 4112640 82 Linux swap / Solaris


Fstab

/dev/md0 /boot ext2 noauto,noatime 1 2
/dev/md1 / reiserfs noatime 0 1
/dev/sda3 swap swap defaults,pri=1 0 0
/dev/sdb3 swap swap defaults,pri=1 0 0
/dev/cdroms/cdrom0 /mnt/cdrom iso9660 noauto,ro 0 0
proc /proc proc defaults 0 0
/dev/fd0 /mnt/floppy auto noauto 0 0

shm /dev/shm tmpfs nodev,nosuid,noexec
0 0

Raidtab

# /boot (RAID 1)
raiddev /dev/md0
raid-level 1
nr-raid-disks 2
chunk-size 32
persistent-superblock 1
device /dev/sda1
raid-disk 0
device /dev/sdb1
raid-disk 1

# / (RAID 1)
raiddev /dev/md1
raid-level 1
nr-raid-disks 2
chunk-size 32
persistent-superblock 1
device /dev/sda2
raid-disk 0
device /dev/sdb2
raid-disk 1

and lastly here is my grub.conf

default 0
timeout 30
splashimage=(hd0,0)/boot/grub/splash.xpm.gz

title=Gentoo Linux 2.6.13-r5
root (hd0,0)
kernel /boot/kernel-genkernel-x86-2.6.13-gentoo-r5 root=/dev/md1 vga=791 splash=
silent
initrd /boot/initramfs-genkernel-x86-2.6.13-gentoo-r5
md=0,/dev/sda1,/dev/sdb1
md=1./dev/sda2,/dev/sdb2



Suggestions and experience would be helpful. Thank you!

[Massimo B.]

Did you mention the problem of Raid0 on two disks with ext3? The Software-RAID HOWTO
There is also the possibility to give mkfs.ext3 the stripesize, but I am not sure if that brings the same result.
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[Attila]

Hiho,

Very cool Howto!

Some notes for sparc64 users:

- use sun disklabel, not Dos (sure, dos works as long you did not try to boot from it)
- if you have problems writing an initial sun disklabel, boot a solaris-cd (you can get it for free from sun.com) and use "format" to write a correct disk-label
- while partitioning: DO NOT TOUCH PARTITION 3 (slice 2 under solaris)
- use /boot (20 mb or so)
- start /boot at cylinder 0 (i can't get silo work on a partition not starting at cyl 0)
- no not mirror /boot (if you do so, you will mirror you partition table too)
- Set partition type 0xfd on all partitions you want to mirror (on both disks)
- to make it possible to boot from both disks, add both /boot's to the fstab (e.g. s /boot and /boot.bkp or so)
- copy kernel & silo.conf onto both /boot's
- Start Silo twice

[ericxx2005]

Thanks for the howto, now getting 93Mb/sec on two 7200.7's!

[Aries-Belgium]

Sorry to bump up an older thread but ...

I'm installing gentoo on a raid system as we speak, so far everything is going great, thanks to this howto!

But I got a question about a worst case scenario: what if grub doesn't won't to boot linux and I have to reconfigure and recompile my kernel. How do I mount the raid partitions again? I think, correct me if I'm wrong, I have to paste the raidtab file again in /etc and then run raidstart /dev/md0. But what if I get an error?

[BlinkEye]

i had to do that a couple of times. last week my reiserfs wasn't bootable and i had to use a livecd. actually, there are two tools around: raidtools (raidstart, raidstop etc.) and mdadm.

[Aries-Belgium]

Okay I was able to get it working and it boots now (had a few problems). I did it with two 80GB harddisks. My boot partition is in raid1 and my root partition is in raid0. And I always thought that raid0 combined the sizes of the two disks, but when I type "df" it shows me that there is only 74GB free space availible. Was I wrong about raid0? Or did I do anything wrong? And if I did anything wrong, does that mean I can start all over again?

[EDIT]
Okay, I did something wrong. md2 also is raid1. I forgot to edit the raid level when I copied it from this tutorial. Can I fix it without losing data? Probably not

[BlinkEye]

if you really have the wrong raid i do not know of a way to resync them without actually backing up everything. you may be interested in this backup howto.
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[Aries-Belgium]

[Zee]

Hi.
I hope I'll get a reply for I'm really desperate. I found sw RAID how-to on the Gentoo-wiki page and I followed it to the word. I'm try ing to setup a RAID 1 array that would be used as / on my home-made NAS. The installation went through without any problems, but when I try to boot udev complains: wrong fs type, bad option, bad superblock on udev

there are NO errors prior this message.

can you please help me,
zee

[BlinkEye]

Please provide the following information:

/etc/fstab
/boot/grub/grub.conf

Just a thought: in case you use a filesystem other than ext2/3 like reiserfs or jfs did you emerge the corresponding utils described in "Chapter 9.d"?
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[Zee]

fstab:
/dev/md0 / reiserfs noatime,notail 0 1
/dev/hdc1 /home reiserfs noatime,notail 0 2
/dev/hdc2 none swap sw 0 0

# NOTE: The next line is critical for boot!
proc /proc proc defaults 0 0
shm /dev/shm tmpfs nodev,nosuid,noexec 0 0

instead of grub I use lilo:
compact
# Should work for most systems, and do not have the sector limit:
lba32
# If lba32 do not work, use linear:
#linear

# MBR to install LILO to:
boot = /dev/hda
map = /boot/.map

install = /boot/boot-menu.b

menu-scheme=Wb

#prompt
# If you always want to see the prompt with a 15 second timeout:
#timeout=150
#delay = 50
# Normal VGA console
vga = normal
# VESA console with size 1024x768x16:
#vga = 791
#default=kernel-2.6.15

image = /boot/kernel-2.6.15
root = /dev/md0
label = Gentoo
read-only # read-only for checking

I use reiserfs and the reiserfsprogs package has already been installed.

I tried with udev version 079 and 087, but it's always the same.

The strange part is that /sys and /proc get mounted w/o problems.

thanks,
zee

[Dikkiedik]

I'm doing a software raid install but in the meanwhile the software howto on the gentoo-wiki site has changed... It's missing some details. Like the emerging of DMRAID etc... Luckely I noticed the link below the page pointing to the original wiki/howto.. the current wiki stinks a bit in my opinion.. but I guess thats because it's new. I love the original howto though. Thanks for the work =), I'm very grateful for it.
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[guid0]

on my machine it was in fact udev that failed. Forgot to compile Unix domain sockets in the kernel (network section) which fixed it for me.