>>> On 12/16/2016 at 01:54 PM, Marcy Cortes <[email protected]> 
>>> wrote:

> It's more complicated with SLES 12 and grub.
> I managed to change it but I'm not sure if all is exactly right.
> 
> UUID's changed so the boot didn't work.
> 
> I changed /etc/default/grub to 
> GRUB_DISABLE_LINUX_UUID=true

That's probably not what you want to do, since currently that results in grub2 
creating entries such as "root=/dev/dasda1".  I've put in a query to our grub2 
maintainer to see if there's any way to convince grub2 to make that an option, 
along with /dev/disk/by-path/ type entries.
 
> And I put the root=/dev/disk/by-path/ccw-0.0.0101-part1 into 
> GRUB_CMDLINE_LINUX_DEFAULT

You could use that or the GRUB_CMDLINE_LINUX variable.  I'm not sure what the 
intent of each of those variables are.  They seem to be handled independently, 
but what that implies I'm unaware.
 
> That seemed to do the trick, but the cmdline looks a bit odd with 2 root= 's 
> in it.

To get rid of the one grub2 wants to generate, update /etc/default/grub to add 
this line:
SUSE_REMOVE_LINUX_ROOT_PARAM="true"

It can be anywhere you want.  I put it at the bottom of mine.
 
Please make sure you follow the directions at the top of that file and run 
"grub2-mkconfig" afterward.

> cat /proc/cmdline
> root=/dev/dasda1 root=/dev/disk/by-path/ccw-0.0.0101-part1 hvc_iucv=8 
> TERM=dumb crashkernel=103M vmhalt=LOGOFF vmpoff=LOGOFF
> 
> Is there some doc for getting off the UUID default and using by-path?
> The UUID isn't great for copying disks or for replication and cloning.

Actually, for replication and cloning, it works just fine, since the file 
system UUID is part of the file system itself.  You were copying individual 
files from one file system to another and that's a whole different proposition.

During the installation, when it comes to setting up partitions, LVM, etc., 
when setting the mount points for / and any other file systems, underneath the 
"Mount Point" field is "Fstab Options."  Select that, and choose the "Device 
Path" option.  That will take care of /etc/fstab.  For the various entries that 
get put into the initrd, you can add a file to the /etc/dracut.conf.d/ 
directory.  For example, /etc/dracut.conf.d/98-persistent.conf.  The entire 
contents of that file are:
persistent_policy=by-path

After you've done that, re-run mkinitrd or "dracut -f" to update the initrd in 
/boot.


Mark Post

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