Install raid1 and lvm for Kubuntu
Hardware configuration

    *
      MB : ASUS M2N32 Workstation Professional
    *
      CPU: Athlon 64 X2 5600+
    *
      HD : 2xWD 74GB Raptor, 2xSamsung 500GB, 1xSamsung 400GB
    *
      RAM: 4 GB DDR2-6400
    *
      Usage: Server

Brief problem description

I started off installing Kubuntu Feisty 7.04. Within the partitioner, I could not set up lvm. I could not get past the error message “Error informing the kernel about modifications to /dev/md2p1 –Invalid argument”, no matter what I did. I even zeroed all partition tables with dd, but whenever I entered LVM config the partitioner recognized md0, md1, md2 and the usage as lvm. I’m not quite sure how this is possible, I even started doubting my new hardware.

After several hours I decided to go back to Kubuntu 6.10, with which I still could not install lvm, but I could properly install the 2 multidisk (raid1) configurations (md0: /, md1: swap, md2: /srv). md2 = /srv was a necessary intermediate step, because lvm did not configure through on Edgy either, so I formatted it with ext3.
Remarks for the walkthrough below

    *
      “>” means “and then”, next menu item or next step
    *
      “|” means option, do first or second ( first | second)
    *
      all commands below as super user. enter sudo -s

Desired configuration of the disks
hdd 	partition 	raid1 	lvm 	mount point
sda 	sda1 	md0 	- 	/
sdb 	sdb1 	md0 		
sda 	sda2 	md1 	- 	swap
sdb 	sdb2 	md1 		
sdc 	sdc1 	md2 	vg1, lv1, lv2 	/home, /srv
sdd 	sdd1 	md2 		
sde 	sde1 	- 	vg2, lv3 	/backup
Install Base

   1.
      Install Kubuntu Edgy (6.10) Alternate Install: F6-F6-Expert Mode
   2.
      Install Raid1 with MD package activated
   3.
      DO NOT install LVM during initial setup
   4.
      Boot into KDE from HD

    *
      Note: if MD oder LVM already activated before and need clean: 2nd shell (Alt-F2) > mdadm - -manage - -stop md0 > mdadm - -manage - -remove md0 before writing to disk in partitioner

Install LVM

   1.
      lvm > pvcreate /dev/sde1 > pvcreate /dev/md2
   2.
      lvm > vgcreate vg_backup /dev/sde1 > vgcreate vg_data /dev/md2
   3.
      lvm > vgdisplay vg_backup to check ### of free extents (following steps same for vg_data, but 2 logical volumes)
   4.
      lvm > lvcreate -l### vg_backup (do not use -LxxGB, use size with -l### which is number of extents)
   5.
      lvm > lvrename vg_backup lvol0 lv_backup
   6.
      lvm > vgcfgbackup to backup volume group configurations
   7.
      lvm > exit
   8.
      umount /home > umount /srv
   9.
      mkfs -t ext3 /dev/vg_backup/lv_backup > mkfs -t ext3 /dev/vg_data/lv_home > mkfs -t ext3 /dev/vg_data/lv_srv
  10.
      mkdir /backup
  11.
      mount /dev/vg_backup/lv_backup /backup > mount /dev/vg_data/lv_home /home > mount /dev/vg_data/lv_srv /srv

    *
      As I use this machine as a server I did not consider to upgrade Edgy to Feisty, but I would expect that this can be done without problems. I’m not sure this is the best way or the fastest, but it worked for me.

Done! Everything works now!