Dmraid: Call for testing.

Luke Yelavich themuso at
Fri Aug 29 09:15:43 BST 2008

Hash: SHA1

Greetings all,
As of today's daily alternate CDs, dmraid is now available for testing. Dmraid is software that makes Bios/Fake RAID configurations available to Linux through the kernel device mapper. This type of RAID is software RAID in another form, where you use the disk controller's BIOS to configure the raid settings, then the OS driver, usually Windows or Linux, then reads metadata from the disks in the RAID set, and constructs the array.

There are some known issues which you don't need to report, which are as follows:
* Installing using LVM on a dmraid array does not work properly. While it appears to install ok, filesystems are incorrectly mounted/LVM incorrectly detects the correct device to use. I have only tried this with a RAID1 configuration, but it may also be a problem with other RAID sets.
* If you install Ubuntu alongside Windows, the installer will not ask you whether your clock should be in UTC etc which indicates that Windows is present, but grub-installer does not configure grub to allow you to boot windows.

Note also that I have only tested dmraid so far with RAID0, and RAID1. I would appreciate any feedback from users using RAID10/RAID0+1, and RAID5 configurations. Please also note that when dmraid loads, it is via udev, and a wrapper script which I have written, to attempt to detect whether an array is fully functional. This script will not bring up arrays that are degraded unless specifically told to do so.

For those who don't have any hardware that supports this, but are able to run a KVM virtual machine, you can fetch a set of qcow2 format disk images from the below URL and try this in a virtual machine yourself:

When full, these disks take up 80GB of disk space.

Bug reports should be filed against the dmraid package in Launchpad.


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