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I will be installing Ubuntu on an external SSD, and I have two options:

  • A regular, "Full" installation
  • A "live install" with persistence

I'd like to understand the difference between the two methods:

  • I know if I use a live install with persistence, I can swap the drive between multiple PCs and select from BIOS. Is this possible with a full install?

  • I will be creating two partitions on the SSD, one for Ubuntu and the other for storage. Among these options, will any one of them restrict me from doing so?

  • What other differences/restrictions are there between the two options? I personally want to go with a normal install if possible.

NotTheDr01ds
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Fumax
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    A full install is an actual installation; the persistent live is still a live session with those changes being saved between re-boots; but still not providing a full installation experience as it's still COW & chains; rather than direct writes. – guiverc Oct 04 '21 at 03:30
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    @guiverc so if I install it fully on SSD... I can use it on any other PC directly booting with SSD? – Fumax Oct 04 '21 at 03:48
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    A LiveUSB's "Try Ubuntu" environment has two purposes: 1) So prospective users can try the Ubuntu experience, and 2) So prospective users can test Ubuntu on their hardware. Some folks use a Live environment for more than that, but it's not tested beyond those two purposes. – user535733 Oct 04 '21 at 03:50
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    "preferred" is a matter of YOUR opinion and perferences. Advice: Try both ways, decide which you prefer, blog about your experience and results and preference. Then stick around here and answer similar questions from other folks who are wondering. More Advice: Ubuntu is fairly quick and easy to install (and re-install) -- there is no vendor lock-in, no Product Key to preserve and protect. So back up your data so you don't overwrite on a whim. – user535733 Oct 04 '21 at 03:52
  • Does this answer your question? What would be the differences between a persistent USB Live Session and a installed Ubuntu in a USB drive? – user68186 Nov 16 '22 at 18:54

1 Answers1

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Persistent Install vs Full install

Ubuntu can be installed to a USB in different ways. A Live install does not save between sessions. A Persistent install extracts the OS from a compressed file and saves data to an overlay file or partition each session, and a Full install installs the complete OS to the USB just like an install to internal disk.

Comparison between Persistent and Full install USB

Advantages of a persistent install:

  1. You can use the persistent pendrive to install Ubuntu to another computer.

  2. A persistent install takes up less space on the pendrive.

  3. You can reset the pendrive by overwriting the old casper-rw file with a new one.

  4. The install to pendrive takes less time.

  5. Slightly less wear on the drive.

  6. Does not require a User account off the shelf, Users and passwords can be added if desired.

Advantages of a Full install:

  1. You can update and upgrade.

  2. If you have problems or wish to modify, the solution is the same as with an internal install, (You can ask for help in the forums).

  3. No ugly startup / install screen.

  4. Better security, you can use full encryption

  5. You can use proprietary drivers.

  6. Swapfiles and partitions work and Hibernation can be enabled.

  7. Many persistent installs are limited to a 4GB casper-rw and a 4GB home-rw persistence file, to get more persistence requires persistence partitions. Once casper-rw is full, the drive will not boot.

  8. More efficient usage of disk space. Does not require reserved space for persistence.

  9. Faster boot, no automatic disk checking or Try Ubuntu/Install Ubuntu screen.

  10. You can run VBox and use virtual machines.

  11. Generally faster boot than Live or Persistent USBs.

  12. More stable, better for day-to-day use. I have run Ubuntu off a flash drive for 5 years making only LTS upgrades.

  13. Requires a user account and login, (with or without a password).

Note that once booted, both methods run at about the same speed. If the computer has lots of RAM Ubuntu should run mainly in RAM and there will not be a big difference between running off internal HDD and USB3 flash drive.

Full Install Method

A quick and easy method to flash a Full install to USB can be found here: Easy Full Install USB that Boots both BIOS and UEFI

A more traditional methods for creating a Full install USB from scratch can be found here: How to Create a Full Install of Ubuntu 20.04 to USB Device Step by Step

Persistent install method

The following tools can be used to make a Persistent install USB: mkusb - https://help.ubuntu.com/community/mkusb, Rufus - https://rufus.ie/en/, Universal USB Installer - https://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/, Ventoy - https://www.ventoy.net/en/index.html, YUMI- https://www.pendrivelinux.com/yumi-multiboot-usb-creator/. and others.

mkusb is my favorite tool for making Persistent USB's https://help.ubuntu.com/community/mkusb. It creates boot partitions that allow it to boot in BIOS or UEFI mode. It puts the OS on a read only ISO9660 partition that is difficult to corrupt. Persistence goes on an ext4 partition who's size is only limited by USB size and it will make a NTFS data partition so you can save data from a Windows or a Linux computer

C.S.Cameron
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