Now let's create our volume group pve1 and add /dev/md1 to it:

vgcreate pve1 /dev/md1

That should show success:

Volume group "pve1" successfully created

Now we need to create our logical volumes. I will use the same sizes and names as the volumes from the lvscan command above.

lvcreate --name swap --size 15G pve1
lvcreate --name root --size 96G pve1
lvcreate --name data --size 804G pve1

If that was successful then the command:

lvscan

returns:

root@proxmox:~# lvscan
ACTIVE '/dev/pve/swap' [15.00 GiB] inherit
ACTIVE '/dev/pve/root' [96.00 GiB] inherit
ACTIVE '/dev/pve/data' [804.02 GiB] inherit
ACTIVE '/dev/pve1/swap' [15.00 GiB] inherit
ACTIVE '/dev/pve1/root' [96.00 GiB] inherit
ACTIVE '/dev/pve1/data' [804.00 GiB] inherit

As you can see we now have two sets of the same logical volumes. One on /dev/sda2 and one on /dev/md1.

Now we need to create the filesystems:

mkfs.ext4 /dev/md0
mkswap /dev/pve1/swap -f
mkfs.ext4 /dev/pve1/root
mkfs.ext4 /dev/pve1/data

If that was successful then it is time to copy the files to the new raid array.

First we mount the new partitions:

mkdir /mnt/boot
mkdir /mnt/root
mkdir /mnt/data
mount /dev/md0 /mnt/boot
mount /dev/pve1/root /mnt/root
mount /dev/pve1/data /mnt/data

Adjusting The System To Use RAID 1

Now we must edit /etc/fstab:

vi /etc/fstab

It should read:

# <file system> <mount point> <type> <options> <dump> <pass>
/dev/pve1/root / ext4 errors=remount-ro 0 1
/dev/pve1/data /var/lib/vz ext4 defaults 0 1
/dev/md0 /boot ext4 defaults 0 1
/dev/pve1/swap none swap sw 0 0
proc /proc proc defaults 0 0

Notice that all the instances of pve are replaced with pve1 and /dev/md0 is mounted on /boot.

Now up to the GRUB2 boot loader. Create the file /etc/grub.d/09_swraid1_setup as follows:

cp /etc/grub.d/40_custom /etc/grub.d/09_swraid1_setup
vi /etc/grub.d/09_swraid1_setup

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'Proxmox, with RAID1' --class proxmox --class gnu-linux --class gnu --class os {
    insmod raid
    insmod mdraid
    insmod part_msdos
    insmod ext2
    set root='(md/0)'
    echo    'Loading Proxmox with RAID ...'
    linux   /vmlinuz-2.6.32-11-pve root=/dev/mapper/pve1-root ro  quiet
    echo    'Loading initial ramdisk ...'
    initrd  /initrd.img-2.6.32-11-pve
}

Make sure you use the correct kernel version in the menuentry stanza (in the linux and initrd lines). You can find it out by running:

uname -r

or by taking a look at the current menuentry stanzas in the ### BEGIN /etc/grub.d/10_linux ### section in /boot/grub/grub.cfg. Also make sure that you use root=/dev/mapper/pve1-root in the linux line.

The important part in our new menuentry stanza is the line set root='(md/0)' - it makes sure that we boot from our RAID1 array /dev/md0 (which will hold the /boot partition) instead of /dev/sda or /dev/sdb which is important if one of our hard drives fails - the system will still be able to boot.

Because we don't use UUIDs anymore for our block devices, open /etc/default/grub...

vi /etc/default/grub

... and uncomment the line GRUB_DISABLE_LINUX_UUID=true:

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.

GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX=""

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_LINUX_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

Run

update-grub

to write our new kernel stanza from /etc/grub.d/09_swraid1_setup to /boot/grub/grub.cfg.

Next we adjust our ramdisk to the new situation:

update-initramfs -u

Next we copy the files:

cp -dpRx / /mnt/root
cp -dpRx /boot/* /mnt/boot
cp -dbRx /var/lib/vz/* /mnt/data

Now we reboot the system and hope that it boots ok from our RAID arrays:

reboot

If all goes well you should be able to see our new logical volumes root and data and /dev/md0 mounted:

mount

root@proxmox:~# mount
/dev/mapper/pve1-root on / type ext4 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
/dev/mapper/pve1-data on /var/lib/vz type ext4 (rw)
/dev/md0 on /boot type ext4 (rw)
fusectl on /sys/fs/fuse/connections type fusectl (rw)
beancounter on /proc/vz/beancounter type cgroup (rw,name=beancounter)
container on /proc/vz/container type cgroup (rw,name=container)
fairsched on /proc/vz/fairsched type cgroup (rw,name=fairsched)

Now we need to remove the volume group pve:

lvremove /dev/pve/root
lvremove /dev/pve/swap
lvremove /dev/pve/data
vgremove /dev/pve
pvremove /dev/sda2

root@proxmox:~# lvremove /dev/pve/root
Do you really want to remove active logical volume root? [y/n]: y
  Logical volume "root" successfully removed
root@proxmox:~# lvremove /dev/pve/swap
Do you really want to remove active logical volume swap? [y/n]: y
  Logical volume "swap" successfully removed
root@proxmox:~# lvremove /dev/pve/data
Do you really want to remove active logical volume data? [y/n]: y
  Logical volume "data" successfully removed
root@proxmox:~# vgremove /dev/pve
  Volume group "pve" successfully removed
root@proxmox:~# pvremove /dev/sda2
  Labels on physical volume "/dev/sda2" successfully wiped

Now we must change the partition types of our three partitions on /dev/sda to Linux raid autodetect as well:

fdisk /dev/sda

root@proxmox:~# fdisk /dev/sda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): t
Partition number (1-4): 1
Hex code (type L to list codes): fd
Changed system type of partition 1 to fd (Linux raid autodetect)

Command (m for help): t
Partition number (1-4): 2
Hex code (type L to list codes): fd
Changed system type of partition 2 to fd (Linux raid autodetect)

Command (m for help): p

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0009f7a7

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          66      523264   fd  Linux raid autodetect
Partition 1 does not end on cylinder boundary.
/dev/sda2              66      121602   976237568   fd  Linux raid autodetect

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

Now we can add /dev/sda1 and /dev/sda2 to /dev/md0 and /dev/md1:

mdadm --add /dev/md0 /dev/sda1
mdadm --add /dev/md1 /dev/sda2

Now take a look at:

cat /proc/mdstat

... and you should see that the RAID arrays are being synchronized.

Then adjust /etc/mdadm/mdadm.conf to the new situation:

cp /etc/mdadm/mdadm.conf_orig /etc/mdadm/mdadm.conf
mdadm --examine --scan >> /etc/mdadm/mdadm.conf

Now we delete /etc/grub.d/09_swraid1_setup...

rm -f /etc/grub.d/09_swraid1_setup

... and update our GRUB2 bootloader configuration:

update-grub
update-initramfs -u

Now if you take a look at /boot/grub/grub.cfg, you should find that the menuentry stanzas in the ### BEGIN /etc/grub.d/10_linux ### section look pretty much the same as what we had in /etc/grub.d/09_swraid1_setup (they should now also be set to boot from /dev/md0 instead of (hd0) or (hd1)), that's why we don't need /etc/grub.d/09_swraid1_setup anymore.

Afterwards we must make sure that the GRUB2 bootloader is installed on both hard drives, /dev/sda and /dev/sdb:

grub-install /dev/sda
grub-install /dev/sdb

Reboot the system:

reboot

It should boot without problems.

That's it - you've successfully set up software RAID1 on your Proxmox system!

Enjoy!