I'm using Linux ... 3.19.0-31-generic #36-Ubuntu SMP Wed Oct 7 15:04:02 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux.

In the file etc\default\grub I find this line:

GRUB_CMDLINE_LINUX_DEFAULT="nomdmonddf nomdmonisw nomdmonddf nomdmonisw nomdmonddf nomdmonisw nomdmonddf nomdmonisw"

Is it safe to remove the duplicate/triplicate entries nomdmonddf nomdmonisw?


This site has the following to say about the issue:

Two new RAID-related options appeared in the kernel options with Ubuntu 14.04 -- nomdmonddf and nomdmonisw. They appear to be underdocumented, and basically only relate to Ubuntu. AFAICT they relate to the plan to change from using dmraid to mdadm to assemble RAID devices; but I've been using mdadm for years.

The "nom nom nom" duplication seems to be caused by:

/etc/default/grub.d/dmraid2mdadm.cfg containing:

GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT nomdmonddf nomdmonisw" which unilaterally appends them to the config if the mdadm package is installed, even if they are already there ( :-( ); and

dpkg-reconfigure grub-pc, which picks up those arguments and puts them into /etc/default/grub, so that they're baked in for another round of adding them

update-grub also adding them onto the command line written into /boot/grub/grub.cfg even if they're already there in the text coming from /etc/default/grub.


There are some Ubuntu bugs #1291434 and #1318351 about this, so it might eventually be implemented better. Making the "ensure these parameters are present" idempotent -- so it only adds them once -- would seem like a good start!

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