Daniel Malisani's picture

Does the kernel supports raid?

I have the message:

El archivo de estado de RAID del kernel /proc/mdstat no existe en su sistema. Su kernel probablemente no soporta RAID.


(in spanish)

Jeremy Davis's picture

The ISO install images use the default (Desktop) Ubuntu kernel 2.6.24 which AFAIK supports RAID (although I haven't tested it).

I just had a quick read online and found this (here) which may be relevant:

Ubuntu 8.04 LTS fails to run on some DELL PowerEdge servers with RAID controllers, such as the 3/Di controller in the DELL PowerEdge 1650, due to a bug in the RAID firmware. To install or upgrade to Ubuntu 8.04 LTS on a system with the affected RAID controller, you will first need to upgrade your RAID firmware

A quick scan over goole results suggests that some othr hardware may also be having some problems.

Someone else here may be able to shed more light on the situation but in the meantime, I'd be inclined to search over on the Ubuntu forums as TKL is basically Ubuntu server under the hood (with some tweaks and customisations - such as using the Desktop kernel).

Icefox's picture

It may be compiled with support for it in the kernel but either not have the module loaded by default or not have the usual tools installed (or both).

Try seeing if the "mdadm" program is installed; if not, try "lsmod | grep md" on the command line and see if it gives any results.  Note that "md" is Linux's software RAID; for hardwarecontrollers you'd need the vendor's drivers.

Just discovered TKL this week and haven't gotten around to giving it a good hard beating, but I'd think that the Ubuntu Server kernel would have support for md...  Out of curiousity, why does it use the Desktop kernel?

Sergey's picture

> either not have the module loaded by default or not have the usual tools installed (or both)

It's true :( but this is a half of the trouble only.

Last hope: loading into live system, switching console, typing

# apt-get install mdadm; modprobe raid[0,1]; mdadm create .......

"/dev/md0 created and started"

switching to install screen ...

... And installer doesn't list software RAID devices. Neither now, nor after reboot

Very bad for small server installation too, returning to Ubuntu Server 10.04 with many manual configurations... :(

PS Sorry for my English, greetings to mainteiners.

Jeremy Davis's picture

Based on Ubuntu 10.04/Lucid so perhaps try again then. If this is something that you're particularly interested in then perhaps you can help the devs get this working once the new version is released?

Jeremy Davis's picture

Especially with VM based install options. Desktop kernel runs better in a wider array of VM environments apparently.

Liraz Siri's picture

If the issues we came across with virtualization have been solved in Lucid we may default to the server kernel instead.

Note that only the ISO build includes the desktop kernel. The VM builds include the linux-virtual kernel. I'm not sure whether or not that one has support for software raid though.

Also, the kernel we include is only the default. You can swap it out for another one if you like via the package manager, just like with any other Ubuntu system.

ET's picture

TKL (8.04) will work with software raid as an add-on. The easiest way to use mdadm with tkl is to create the tkl appliance by installing the OS onto a usb flash drive. Then install mdadm, partition and format the internal disks then create the raid arrays on the internal disk partitions. If the disks containing the software raid get setup correctly then the tkl instance can be moved to the internal raid disks. It may be a better option to use a usb header adapter to plug the flash drive directly onto the motherboard and leave the entire internal hard disk array for file usage. I've only done this with the file server appliance thus far.

aFoP's picture

For RAID1 usage, you can install TKL with LVM on a single disk, and then use below scripts to turn it into RAID1 system with mdadm:


I've created them based on tutorial I've found on howtoforge.com.

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