Article Number: 000130987
This article provides information about the Ubuntu 16.04 operating system and Dell's OptiPlex Desktop systems, using the Intel Matrix RAID setup.
Ubuntu 16.04 and the type of RAID used on our OptiPlex desktops is not a natural fit. The OptiPlex uses Intel Software to provide a version of RAID 1 or 0. Ubuntu is not set up by default to recognize this sort of RAID. Various issues branch off from this original issue. While you can upgrade to the latest LTS version, the OptiPlex series of desktops have been certified for use with Version 12.04 through to 16.04. Below we will give information and links to workarounds and various installation steps to get around this RAID issue.
Ubuntu cannot be installed on a VHD (RAID 1 or 0) with the default setting of the partition table that Ubuntu uses. When you set up a RAID configuration under the Intel Matrix Manager (Pressing the CTRL+I function before boot.) and then start the machine from the Ubuntu LIVE media and start the installation. You will get an error on the next step Ubuntu cannot be installed on this partition.
Instead you need to set up the RAID partitions using the Intel Matrix Controller Interface and then carry on with the rest of the instructions below.
Start by configuring your Software RAID. Go to the Canonical article linked below and follow the instructions from the start of the article until it gets to the Bootloader Section:
In order to work around this issue, you need to change the default setting to /dev/mapper/xxxxxxxx_Volume1 and set up the swap, Boot, and EXT4 partitions manually. Check out the article below on how to change this setting:
Check out the guides below for more information about custom Ubuntu Installs:
Previously because the platform does not support VHD, the system fails to rebuild RAID1. If you replace one of the two hard drives, the system would remain on rebuild status. If you reset the new hard drive in the RAID controller interface by pressing the CTRL+I function before the system boots. Which forces the rebuild, it does not work. The RAID1 volume remains on rebuild status.
However, if we say that you have used the correct methods to install (As recommended in Section 2.) Ubuntu with the latest BIOS. Then we recommend the following steps to resolve or test this particular issue:
In order to recreate a fault, we can remove a hard drive from the array and reboot the machine.
The first thing is to check the system boots in degraded mode.
When in degraded mode there is only one hard drive active in the RAID1 group (most commonly md0). Where sdX is the inactive hard drive, the following command in Terminal (CTRL+ALT+T) can remove it from the RAID1 group:
sudo mdadm --zero-superblock /dev/sdX
If it boots fine, add the hard drive back and the let the Operating System resync the RAID content.
To resynch the content from the active hard drive and recover the group, you can run the following command in Terminal (CTRL+ALT+T):
sudo mdadm --manage /dev/md0 --ass /dev/sdX
To check the RAID status run this Terminal command (CTRL+ALT+T):
Some people using 12.04 can only see clone mode.
This issue can be resolved by moving from integral graphics to an add-on PCI graphics card or by updating to Ubuntu LTS Version 14.04 or 16.04.
Here are some articles that go into Ubuntu Video in greater detail:
21 Feb 2021