Root RAID HOWTO cookbook: Quick Start for ROOT RAID

3. Quick Start for ROOT RAID

If you use RedHat, see the Howto set up RedHat section in Appendix H. I have not tried this. If you use it successfully, please let me know so I can update this document.

If you don't want to try and build and debug the rescue system, you can get a generic one created from Slackware-3.4 from:

ftp.bizsystems.com/pub/raid/raidboot-0.01.tar.gz

Perform the following steps:

Compile the raid enabled kernel with built in support for your disk subsystem
Test that the raid array will configure and mount correctly
Build your OS on the raid system
Correct the entries in fstab to show /dev/md0 as the root device. Make sure that the partition(s) you use for booting are included in fstab.
Modify your shutdown halt and reboot script(s) (mine is /etc/rc.d/rc.6) as shown in Modifying the rc-scripts for SHUTDOWN

Copy the following from you development filesystem to the rescue system AND the new raid system

        cd /root/raidboot
        mkdir mnt
        gzip -d rescue.clean
        losetup /dev/loop0  rescue.clean
        mount /dev/loop0    mnt

copy these files

        cp -p /etc/*         mnt/etc
        cp -p /etc/rc.d/*    mnt/etc/rc.d 
                {or as appropriate for your system}
        cp -a /lib/modules/* mnt/lib/modules

Some Linux distributions include a test for the ro/rw status of the root file system. The rc startup files need to have this test removed for the initrd rescue system. See the instructions in the section on Correctons for Rescue System.

Correct the entries in fstab to show /dev/md0 as the root device. Make sure that the partition(s) you use for booting is included in fstab.

Create /etc/raidboot.conf which describes the raid boot configuration. This file may NOT contain comments in the first three lines, after that it doesn't matter.

raidboot.conf

        /dev/sda1 /dev/sda2
        raidboot
        raid5.conf
# comments may only be placed 'after' the three
# configuration lines.
#
# This is '/etc/raidboot.conf'
#
# line one, the partition(s) containing the 'initrd' raid-rescue system
#       It is not necessary to boot from these partitions, however,
#       since the rescue system will not fit on floppy, it is necessary
#       to know which partitions are to be used to load the rescue system
#
# line two, the path to the raidboot config information
#       Where the shutdown status, etc... is located at boot time
#       It does NOT include the mount point information, only 'path'
#       /mntpoint/'path'
#
# line -3-, name of the raid configuration file
#       Current raid configuration file i.e. raid1.conf, raid5.conf

A few more things to do and the raid systems is ready to boot.

Create rc.raidown, as described in Appendix F, and copy it to /etc/rc.d on the rescue, development, and raid system. Unmount the rescue system and zip it.

        umount mnt
        losetup -d /dev/loop0
        mv rescue.clean rescue
        gzip rescue

Copy the rescue file to the raidboot partitions.

        cp rescue.gz /mnt_point(1)/raidboot
        cp rescue.gz /mnt_point(2)/raidboot

Activate the raid array.

        mdadd -ar

Save the good reference status to the raidboot partition

        cat /proc/mdstat | grep md0 > /mnt_point(1)/raidboot/raidgood.ref
        cat /proc/mdstat | grep md0 > /mnt_point(1)/raidboot/raidgood.ref

Lastly, configure the boot program as outlined in Boot Time Configuration Parameters and reboot your system onto the raid array.

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