Disk partitioning for 12.04 install

Question

I have 6 partitions with grub from an existing Linux OS on /dev/sda8. I want to install 12.04 on /dev/sda1 but since this partition has 31G allocated i want to resize it to 10G and create 2 more partitions from the remaining space. I want to know if by doing this will all my existing partitions get shifted and thereby i might have to reinstall them again or is it just a matter of reinstalling the grub on one of them (say Ubuntu) and add the remaining ones?

Additional information:

I've sda1, sda5, sda6, sda7(swap), sda8, sda9, sda10, i plan to delete sda1 and recreate 3 partitions and have 12.04 installed in one of them, the existing ones might also get shifted, as a result grub on sda8 might not work so my machine would be completely unusable until grub is fixed.

Will a resulting not optimal partition order cause any of the existing Linux OS's to not boot or is it just a bad partition table arrangement which won't really affect any OS in the disk?

I had a bad experience last time around when disk numberings got rearranged and i had a tough time recovering everything. Don't remember what happened, so wanted to avoid any such issue this time.

Edit: @Elijah/@Takkat - This is my first time using this website so didn't know i had to edit my original questions for additional information. I'll do that going forward. However i didn't find any delete option for two of my answers to remove them. Can you please remove those two answers? Thanks in advance.

Answer 1

I repartitioned a disk recently in a way that caused the linux partition to change it's number (sda5 to sda3 or similar) and grub couldn't find it's files to boot. I think it happened because I moved the linux partition data from an extended partition to a primary.

But anyway, it was easy enough to fix by booting off a live cd and updating grub to the right setup. Nothing was lost.

Answer 2

Since you have 6 partitions, you must be using extended partitions, since only 4 primary partitions are possible. You also mention that your existing OS is in `/dev/sda8', from which I can conclude that your list of partitions is probably:

/dev/sda1 - primary - 31Gb as you say
/dev/sda4 - extended partition - i.e. container for logical partitions
/dev/sda5 - logical
/dev/sda7 - logical
/dev/sda8 - logical - root of Linux OS (you said)
/dev/sda9 - logical
/dev/sda10 - logical

If this set up is what you actually have, then you can delete or resize /dev/sda1 and then create 2 new primary partitions, /dev/sda2 and /dev/sda3 without the numbering or location of the other partitions changing.

In which case, your new partition scheme would be:

/dev/sda1 - 10Gb
/dev/sda2 - part of freed 21Gb
/dev/sda3 - rest of freed 21Gb
/dev/sda4 - extended partition - unaltered
/dev/sda5 - logical - unaltered
/dev/sda7 - logical - unaltered
/dev/sda8 - logical - unaltered
/dev/sda9 - logical - unaltered
/dev/sda10 - logical - unaltered

Note that, if your extended partition is /dev/sda2 instead of /dev/sda4 you can still make changes without affecting the numbering of /dev/sda5 and above. The only difference will be that the primary partition order may not be optimal, i.e. the start of your new /dev/sda3 and /dev/sda4 will be lower than the start of /dev/sda2.

Answer 3

You will not lose any boot-loader information by creating new partitions from existing ones. The boot-loader path is installed on the very first part of your hard disk. This points to the actual location of grub. As long as you do not remove grub, you will not lose access to the "installs".

This becomes tricky when there is multiple hard drives with multiple pointers. I would make it a point to specify all of your installations to use the boot-loader path on a single hard drive. That way, only one grub boot-loader is ever used.

Basically, hard drive "A" says --> grub is here on this disk. Grub says, here is the booting protocall for these installed OS's. Hard drive "B" may specify a different grub location or the same one. Keep it simple, use sda for all of your boot-loader needs.