Re: Questions on RAID 1 - Mirroring

"K. Allan Wilson" wrote:
> 
> What would be the best way to put lilo on the second drive also and make
> it bootable without  messing with lilo on the first harddrive. I am also
> unable to boot when I try to mirror the /boot partition. It hangs on a
> kernel panic. The only way I am able to setup raid is if I only mirror
> the / partition. Thanks for the help
> 

Allan. 

I've done to an internet server what you're trying to do now.  Below
are the notes I made to myself when developing/testing the procedure. 
Actually, I was replacing a single 18Gb drive with two 36Bg drives
that were to be RAID1.  So the steps below are a little extensive as
they include the swap.

If you have any questions about these notes (and I imagine that you
will) feel free to contact me off-list.

Barry



Install newer large drive into system.
        o Original drive will be /dev/sda
        o New drive (n1) will be /dev/sdb

Create a boot disk for the existing system.
        o mkbootdisk $(uname -r)
        o TEST THE BOOT DISK!

Partition the new drive in whatever way you wish.
        o fdisk /dev/sdb
        o make the appropriate partitions, but be aware
                that changes to existing structions will require
                changes to fstab.
        o Mark the new partitions as type 83 or 82, as appropriate.

Copy the data from the existing disk to the new one.
        o Format the new paritions
                mkfs.ext2 -L LABEL /dev/sdb*
                mkswap /dev/sdb*
        o cd /source;find . -print -xdev | cpio -pdm /mnt/t
                - repeat for each partition
                - be sure to unmount /boot, etc so they aren't copied.

Shutdown, them move new disk to position of old one.
Move second new disk (n2) into place.
        o Boot using boot disk.
        o fdisk on n2, create same paritions but make type "fd"
        o create appropriate /etc/raidtab entries
        o mkraid -R on /dev/md0, /dev/md1, /dev/md2
        o Copy the data once again.

Create a second boot disk, this time equipped for raid:
        o mkbootdisk --verbose --mkinitrdargs '--preload raid1'
$(uname -r)
        o Boot using this diskette, kernel args:
                linux root=/dev/md1 single (md? as appropriate)

Set the first drive as available:
        o change "failed-drive" to "raid-drive" in raidtab
        o raidhotadd /dev/mdN /dev/sdaN as appropriate
        o Wait unti the array has been rebuild.

Make the system bootable from the drive.
        o change the grub.conf file to boot from md0
        o need to create a new initrd image to include raid1
                - mkinitrd --preload raid1 kernel name


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