Linux Extended partition ???

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Re: Linux Extended partition ???

Postby jdmckay » Mon Jan 11, 2016 9:43 am

Thanks Tom.
jdmckay
 
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Re: Linux Extended partition ???

Postby jdmckay » Mon Jan 11, 2016 4:02 pm

Thx again Tom.
jdmckay
 
Posts: 14
Joined: Sat Jul 20, 2013 9:05 am

Re: Linux Extended partition ???

Postby jdmckay » Wed Jan 13, 2016 6:36 am

Just a quick followup:

I've been on steep learning curve last couple weeks, both getting up to speed w/Linux and getting BM running solid in EFI environment with EMBR. Appreciate your help & good articles.

WRT your GRUB2 instructions here:
http://www.terabyteunlimited.com/kb/article.php?id=408
... and logical partitions containing multiple Linux installations I'll add this:

I assume in EMBR setup, a BM boot item for Linux in a primary partition sees in it's MBR boot record only partitions set up (eg. no other bootable Linux partitions in MBR).

In extended partitions however (I currently have 3 separate Linux installations in extended > Logical partitions), BM boot item setup takes only the entire Extended partition, not just Logical partitions within. So when installing GRUB following your instructions, each installed bootable Linux install produces a GRUB menu showing option for every bootable logical partition, not just option for partition being installed. So, after following instructions in your article and executing grub-install, each grub menu will have options to boot every Linux installation in the Extended partition,. This works, but is not what I wanted and I would think the same for others.

This is predictable in GRUB Search instructions in your article, as each execution returns each bootable logical partition... not just partition being installed.

This is how I solved this (I'm new to GRUB): good GRUB guide here:

https://help.ubuntu.com/community/Grub2/Setup

In short, execution of grub-install runs scripts in /etc/grub.d which (along with a couple other processes) builds a file:
/boot/grub/grub.cfg
This file is read at boot time, and used to configure the installation's grub boot menu a user sees.

If you look in: /etc/grub.d, there is a script named: 30_os-prober. This script finds bootable partitions in the MBR and adds them to the grub menu when grub-install executes. As far as I could discover, there is no way to prevent this running grub-install: only by editing the /etc/default/grub file after running grub-install. The Ubuntu Grub2 setup link above has a section:

16: GRUB_DISABLE_OS_PROBER=true

... which describes this setting, it's effect which is prevent 30_os-prober from running. With that said, if you do not want multiple grub menu entries from other Linux installations in an extended partition, edit the file:
/etc/default/grub
and insert: GRUB_DISABLE_OS_PROBER=true

eg: from command line, execute:

> (...)$ gksu gedit /etc/default/grub &

Insert: GRUB_DISABLE_OS_PROBER=true

.Save & quit gedit. /etc/default/grub should then look something like this:

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
GRUB_TIMEOUT=8
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX=""
GRUB_DISABLE_OS_PROBER="true"

....

run grub-install again & reboot. Your grub menu should now contain options only to boot the partition in which you have just installed grub. The Ubuntu article describes other options that can limit boot options listed for the given partition, hide grub menu entirely (direct boot), and/or set timeout if hiding menu so keystrokes can be executed for other boot options in a solid installation.

Ok, hope maybe this will save a few folks some time digging around google if they wish outcomes I describe.

Thx again.
jdmckay
 
Posts: 14
Joined: Sat Jul 20, 2013 9:05 am

Re: Linux Extended partition ???

Postby TeraByte Support(TP) » Thu Jan 14, 2016 5:14 am

jdmckay wrote:

> 16: GRUB_DISABLE_OS_PROBER=true
>
> ... which describes this setting, it's effect which is prevent 30_os-prober from
> running. With that said, if you do not want multiple grub menu entries from other
> Linux installations in an extended partition, edit the file:
> /etc/default/grub
> and insert: GRUB_DISABLE_OS_PROBER=true

Yes, adding that line to /etc/grub/default is the cleanest way to do it. The default for grub is always to look for other OS on the system and add them to the menu, but that can start to get out of hand when you get more than 2 or 3 on there.
Tom Pfeifer
TeraByte Support
TeraByte Support(TP)
 
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Joined: Wed Aug 31, 2011 9:22 am

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