Multi-OS

Install multiple OSs is simple since lots-of OSs have a GUI installer. In most time, someone does not need to install the OS in the hardware, if he only want to try it at first. This section summarizes the content about Live USB and Disk layout.

Live USB

The first thing of installation OSs is having a Live USB that contains multiple ISOs. Vectoy is an open-source tool that can load multiple Live USBs The USB with Ventoy also can be used for backup files.

The only drawback of ventoy is the grub may have a incorrect boot configuration. This makes the installed OS can be boot with recovery mode but cannot boot with the normal mode. To avoid this, just edit the grub (type e when boot) and delete the command rdinit=/vtoy/vtoy.

Disk Partition

Most Linux distributions provides a GUI installer, so the installation is quite easy. The only thing worth noting is carefully about the disk partition without formating the partition and lossing data. Usually, all the home directories of all OSs can be listed in the same partition with different folders. An example partition can be as follows

@itemize @bullet @item nvme0n1 @itemize @minus @item nvme0n1p1 (512 MB) @itemize @minus @item /boot/efi @end itemize @item nvme0n1p2 (16 GB) @itemize @minus @item /swap @end itemize @item nvme0n1p3 (500 GB) @itemize @minus @item /home @itemize @minus @item /home/user_ubuntu @item /home/user_suse @item /home/user_arch @item … @end itemize @end itemize @item nvme0n1p4 (100 GB) @itemize @minus @item / # root for Ubuntu @end itemize @item nvme0n1p5 (100 GB) @itemize @minus @item / # root for OpenSUSE @end itemize @item … @end itemize @end itemize

The most important thing is: DON’T FORMAT the home directory in nvme0n1p3 and the /boot/efi directory in nvme0n1p1 when install a new OS. This partition can provide the capability to reinstall all OSs without affecting the user data.

Update grub

After a new installation, it is better to update the grub at any OSs. The follow command can be used only once at one of the OSs. In Debian, use

sudo grub-mkconfig -o /boot/grub/grub.cfg sudo grub-install /nvme0n1

In OpenSUSE, use

sudo grub2-mkconfig -o /boot/grub/grub.cfg sudo grub2-install /nvme0n1

Reinstallation

Most time there is no need to reinstall my OSs, but sometimes the OS cannot be boot due to strange issues. In this time, the OS can be reinstalled with the same partition and user name as the old version. For example, the root of the new ubuntu will be listed in nvme0n1p4, and the /home will be listed in nvme01n1p3. The user name is ‘user_ubuntu’, so the configuration of the old OS can be reused for the new OS.