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I would like to follow this piece of advice on mdadm Wikipedia article (to get mdadm & RAID working on my Karmic workstation):

To solve this problem, you need to build a new initrd without the dmraid-driver. The following command does this on a system with the "2.6.18-8.1.6.el5"-kernel:

mkinitrd --omit-dmraid /boot/NO_DMRAID_initrd-2.6.18[..].img 2.6.18[..]

However, turns out Ubuntu uses mkinitramfs; initrd-tools (and thus mkinitrd) is no longer available for it.

Can I use mkinitramfs to build initrd omitting dmraid? The man page does not mention such option at all. Or if not mkinitramfs, some other way to do it on Ubuntu 9.10?

(Follow-up to this question.)

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Nor does update-initramfs man page (…) help much – Jonik Jan 29 '10 at 9:07
up vote 5 down vote accepted

Aha! It occurred to me to simply try removing the dmraid Ubuntu packages to see if it helps, and it seems that it did.

This is what I did (after finding out what the packages are):

sudo apt-get remove dmraid libdmraid1.0.0.rc15 

I then updated initrd like this:

sudo update-initramfs -u
update-initramfs: Generating /boot/initrd.img-2.6.31-17-generic

Now, after reboot, mdmadm doesn't give the "Device or resource busy" error message anymore. :-)

NB: I'm not sure if update-initramfs -u was necessary (but it certainly didn't do any harm either).

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This also solved my original problem (not being able to set up a RAID1 partition); for details, see:… – Jonik Jan 30 '10 at 0:08
Thank you thank you thank you! – meanbunny Jun 19 '15 at 15:45

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