Cfrgtkky

I have a Core 2 based desktop PC with 4 GB RAM and 160 GB hard drive containing Linux Mint 17.1 Mate which I've been using happily for several years.

I've bought a second, empty, 80 GB hard drive to put into the PC on which I plan to install Ubuntu Mate. I'll remove the 160 GB drive, replace it with the 80 GB drive, install a fresh Ubuntu Mate on the 80 GB drive, then replace the 160 GB drive as the main drive with the 80 GB drive as the "second" drive. They'll both have their own MBR.

I want to be able to switch back and forth "at will" between the two distros as completely separate entities, not sharing any files whatsoever. Is this possible?

I've read a ton of often complex, often differing posts on how to dual boot on one drive, mostly between Linux and Windows, but none begin to explain switching between two Linux distros on two separate drives. I presume it involves some variation of GRUB but am reluctant to try before asking.

Any help would be much appreciated.

You can have two bootable drives and use your BIOS to select which drive to boot from but it is easier just to let Grub handle everything.

If you want grub to select the distro for you:

• Leave your 160 GB as the first drive


• Install you 80 GB as the second drive


• Boot from Live DVD / Live USB and install Ubuntu to the second drive

Although you can remove the 160 GB drive, swap in the 80 GB, install Ubuntu, swap out the 80 GB, swap in the 160 GB and put the 80 GB into second drive bay that would be the last resort if Ubuntu had problems installing to the second drive.

Things to keep in mind when updating grub:

• When you are operating on the first drive use sudo update-grub
  


• When you are operating on the second drive use sudo grub-install
/dev/sda
  

The first option on grub menu will be first drive (Mint) or second drive (Mate) depending on which drive grub update/install was last run on. The other distribution will be in the advanced options menu.

Understand this answer is typed from memory as it is impractical to take my laptop apart to swap drives around and repeat my installations. If you encounter any difficulties, no matter how small, don't hesitate to post a comment below.

Do you have os-prober package installed? It allows GRUB to autodetect other Windowses and Linuxes and list them automatically. Redo grub-mkconfig, and it will make os-prober to run.

You must have another Linux partitions not mounted for os-probe to detect.

As per my understanding you will eventually end up with two "independent" disks, each having its own MBR and linux distro installed. Right?

If that's the case you can just select from which disk you want to boot during the BIOS initialization/loading phase. Usually in most BIOSes pressing F12 during that phase, brings up a boot device selection menu.