Many people claim that it is impossible to install Ubuntu onto RAID 1 with the Desktop CD. Is this really true? If not, how can it be done?
Edit: This guide does not take UEFI boot into account. Additional or different steps may be required if UEFI boot is desired. This guide assumes legacy boot!
It is true, that the
ubiquity installer does not know about
mdadm software raid devices. Also it is true, that the live-cd is missing the
mdadm raid administration tool. However, doing some work by hand, it is very much possible to install Ubuntu on RAID1.
In the following I will assume two identical hard disks (
/dev/sd[ab]) which will be used completely for our new install. To simplify the recovery if one drive fails, there will be only one
/dev/md0 which will then be partitioned for
swap and data storage, e.g.
After booting up the live-cd and (if necessary) configuring network access, open up a terminal and assume root access
apt-get install mdadm
Now we create a single primary partition each of /dev/sda and /dev/sdb from sector 2048 to the end of the disk, for example using
sudo fdisk. I also like to already set the partition type to
fd for linux raid autodetection. The keystroke-sequence in
fdisk (if the disk is emptyin the beginning, meaning no partitions) is
n <return> p <return> 1 <return> 2048 <return> <return> t <return> fd <return> w <return>.
Now we create the
mdadm --create /dev/md0 --bitmap=internal --level=1 -n 2 /dev/sd[ab]1
I noticed, that the
ubiquity installer also does not quite manage to create partitions inside this
/dev/md0, so I also did this by hand - again using
fdisk. So on
/dev/md0 create the following partitions:
/dev/md0p1for your root filesystem, the size of course depending upon how much software you are going to install.
/dev/md0p2for swap, the size of course also depending on what you use the machine for and how much ram it's got
/dev/md0p3for /home, all the space that's left
After that we can begin the Installation. Make sure to start the installer from the terminal with the
-b option, because installing the bootloader will fail anyway:
Make sure to go for manual partitioning and "use" the 3 partitions you just created and tick the
format checkbox for
/home so a filesystem will be created.
After the installation the system is not yet bootable, so do not restart the box right away. We need to
chroot into the installed system and fixup some stuff:
sudo -s mount /dev/md0p1 /mnt mount -o bind /dev /mnt/dev mount -o bind /dev/pts /mnt/dev/pts mount -o bind /sys /mnt/sys mount -o bind /proc /mnt/proc cat /etc/resolv.conf >> /mnt/etc/resolv.conf chroot /mnt apt-get install mdadm nano /etc/grub.d/10_linux # change quick_boot to 0 grub-install /dev/sda grub-install /dev/sdb update-grub exit
Now the newly installed system is ready to boot. Have fun!
Do not install Ubuntu Desktop CD with RAID 1. My advice:
- Use the Ubuntu Server CD to have a guided RAID 1 install. The manual for this is here (ignore the LVM part, not needed) :
- After that install the Ubuntu desktop environment with
sudo apt-get install ubuntu-desktop
- Reboot and you have a Ubuntu desktop (installed with the server cd).
I haven't tried, but just came accross http://www.salamander-linux.com/.
Salamander is a modified version of the default installer for Ubuntu Linux, Ubiquity. This modified installer allows users to easily install Ubuntu Linux onto a Software RAID array. No special hardware is required -- the Salamander installer can be used on any system with multiple hard disks.