I have home server (Ubuntu Server 10.04) which boots from single 80Gb HDD drive, now I want to make it boot from 2x500Gb RAID-1. I've already successfully created it through MDADM.
But how can I move system to this array so that it can boot?
I've seen some guides in the internet about adding second hdd and making RAID1, but this is not my case...
Briefly:
make a backup of anything important
make a boot cd or usb stick and test it
make the mirror pair and a partition on it
(optional) make an lvm pv on the partition, then a logical volume on that
dd your existing root filesystem onto that new lv
resize2fs it to grow it to use the new space
reboot, interrupt grub, and set the root= parameter to point to one of your new disks
you should now be up using the new disk; now reinstall grub onto the boot sector of one of the mirrored disks, pointing at the new system
change the machine's bios to boot from one of the mirrored disks
There is some risk these rearrangements will leave your system temporarily unbootable so you should only start on this if you're reasonably confident doing low-level rearrangements and/or you have a second machine you can use to ask for help.
Ask if you need more help on any of these points. If none of them make any sense, you should probably just do a fresh install onto the new disks, unless you have a big appetite for adventure. ;-)
Clone the first disk with dd and then restore it on the raid solution.
