[SOLVED] Problems installing Arch with software raid 5

The Avatar of Time · 2008-01-12 22:02:26

Hello, this is the first time I have ever posted in a forum, so I hope that I have not posted this somewhere where I should not have. I am also new to Linux. That being said I am having trouble installing Arch and using software raid 5 with it. The only guides that I can find are for booting from the raid. This is not what I want to do. I want to have the swap, /, and /home on a non-raided hard drive and have a raid 5 array for storage.

I have 5 hard drives:
1 150GB Raptor that I am using for swap, /, and /home.
4 500GB that I want to use as software raid 5 and then mount to /media/media-server (is that a bad place to try to mount it?)

Now I dont have any trouble setting up the array. I have /arch/setup running in terminal 1 so I configure the network (I am using ftp install) and partition the raptor and then set all 4 other drives to raid auto detect. and then go to terminal 2 and do a 'modprobe raid5' and then 'mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde' the array is created just fine. So I jump back to terminal 1 and mount the swap / and /home to the raptor and then md0 to /media/media-server. I then install the base packages (except for lilo). Now I have no idea what to do in system configuration so I leave it alone except for the timezone and adding dchp to eth0 and setting root password. Then I install grub to sda (which I also do not edit apart from adding vga=795 to kernel. Then I reboot and when the system gets to CHECKING FILESYSTEMS i get this:

/dev/sda2: Reiserfs super block in block 16 on /dev/sda2 of format 3.6 with standard journal Blocks (total/free): 12500576/12395333 by 4096 bytes Filesystem is clean

/dev/sda3: Reiserfs super block in block 16 on /dev/sda3 of format 3.6 with standard journal Blocks (total/free): 21105392/21096536 by 4096 bytes Filesystem is clean

FILESYSTEM CHECK FAILED
please repair manually and reboot. note that the root file system is currently mounted read-only. to remount it read-write type: mount -n -o remount,rw / when you exit the maintenance shell the system will reboot automatically

Also if I enter the maintenance and do a 'mdadm --misc --detail /dev/md0 it says cannot open /dev/md0: no such file or directory and if i do that from the Arch install disc it will say device not active.

I have no idea what is wrong and any help would be greatly appreciated. I would be happy to provide any information I may have left out.

Last edited by The Avatar of Time (2008-02-16 23:00:07)

mips1 · 2008-01-12 22:28:56

I don't know if you have seen this, http://wiki.archlinux.org/index.php/Ins … AID_or_LVM

The Avatar of Time · 2008-01-12 23:39:26

Yes that is one of the guides I used as reference. I do not know how much of it would apply to me though since I do not plan on installing the OS on the raid array or using LVM, The 150GB drive that swap / and /home are on is not in the raid array. The array is just going to be for storage. Though perhaps I am looking at the problem wrong and raid is not causing the problem but I can not figure out why the filesystem check fails. I went back into /boot/grub/menu.lst and noticed that root was set to 'ro' so I changed it to 'rw' and when I reboot the filesystem check still fails and still says that root is mounted read-only. Root and /home are the two devices it checks and they both say Filesystem is clean and then immediately after that FILESYSTEM CHECK FAILED still comes up. I am fairly certain that there is nothing wrong with any of the hard drives (I have used the 4 500GB hard drives in a bios raid array for Windows XP and they worked fine).And after making the raid array during installation it shows up as clean and seems to be working fine. So I guess I don't understand what file system is causing the FILESYSTEM CHECK FAILED. I have installed this way twice now to see if something was corrupted the first time but I get the same result.

Still no luck. Let's say that I instead don't bother with raid right now and simply install Arch on the 150GB, can anyone point me in the right direction for setting up my storage raid after installation? Or is it considerably more difficult that way?

Last edited by The Avatar of Time (2008-01-13 00:50:54)

vogt · 2008-01-13 02:07:54

The Avatar of Time wrote:

do a 'modprobe raid5' and then 'mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde' the array is created just fine.
Also if I enter the maintenance and do a 'mdadm --misc --detail /dev/md0 it says cannot open /dev/md0: no such file or directory and if i do that from the Arch install disc it will say device not active.
I have no idea what is wrong and any help would be greatly appreciated. I would be happy to provide any information I may have left out.

So It looks like you missed the step of assembling the raid array. That would require mkinitcpio hooks....

Or, because your root isn't raid, it is almost recommended to do it after the installation. To be able to boot your current installation, first comment the stuff referencing /dev/md0 in your /etc/fstab.

Boot the install cd.

mount /dev/sdax /mnt

sed -e 's_/dev/md0_\#/dev/md0_'  /mnt/etc/fstab

Or just edit it with nano, and add a # in front of all references to /dev/md0...

Then you should have a running arch install.

Within that environment (pretty well the same as the installer).

man mdadm
man mdadm.conf

are pretty definitive resources for raid configuration.

Your issue seems to be that the device isn't assembled (and t to be checked, so they fail)

mdadm --assemble /dev/md0 /dev/sdb /dev/sdc /dev/sdd /dev/sde

needs to happen sometime before you try to mount or check the filesystem. So, try to assemble the array with that command.

You should then be able to mount /dev/md0, as you already have.

That process can be done by specifying the array at boot to the kernel in /boot/grub/menu.lst

# (0) Arch Linux
title  Arch Linux  [[/boot/vmlinuz26]]
root   (hd0,0)
kernel /vmlinuz26 root=/dev/sda2 ro md=0,/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde

That might fail without the raid hook in /etc/mkinitcpio.conf (like the examples in the file)

And adding the information about the array to /etc/mdadm.conf cannot hurt:

mdadm --scan --detail >> /etc/mdadm.conf

And then rebuilding the initcpio:

mkinitcpio -p kernel26

Last edited by vogt (2008-01-13 05:13:56)

The Avatar of Time · 2008-01-30 02:58:49

Sorry to take so long, but thank you for the reply. How would I mark this as Solved?

Last edited by The Avatar of Time (2008-01-30 03:00:05)

lilsirecho · 2008-01-30 04:36:03

Open the initial post and edit the title.

Arch Linux

#1 2008-01-12 22:02:26

[SOLVED] Problems installing Arch with software raid 5

#2 2008-01-12 22:28:56

Re: [SOLVED] Problems installing Arch with software raid 5

#3 2008-01-12 23:39:26

Re: [SOLVED] Problems installing Arch with software raid 5

#4 2008-01-13 02:07:54

Re: [SOLVED] Problems installing Arch with software raid 5

#5 2008-01-30 02:58:49

Re: [SOLVED] Problems installing Arch with software raid 5

#6 2008-01-30 04:36:03

Re: [SOLVED] Problems installing Arch with software raid 5

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