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I have made a persistent live stick with Ubuntustudio 20.04 from ubuntustudio-20.04.2.0-dvd-amd64.iso.

I applied some changes to it (e.g. install Chromium and uninstall Firefox, because it caused memory freeze on a Lenovo T430 laptop in Jitsi meetings with camera enabled). Yeah: it took an awful lot of time installing and uninstalling software (I had to let it run over night) on a thumbdrive with persistence, although I used an USB3-device.

Now I have almost reached my target. But I noticed a message booting from that pendrive (it was not there in the precedent bootings from it)

./boot/grub/x86_64-efi/div.mod: OK Checking ./boot/grub/loopback.cfg ./boot/grub/loopback.cfg: OK

Check finished: errors found in 1 files! You might encounter errors.

The system booted despite that message. Unfortunately the time consumption for booting has grown to almost 4 minutes. Initially it was less than 2 minutes!

There has always been a file md5sums.txt at the root of my thumbdrive. From another system, I went to the directory at the root of the thumbdrive and then applied md5sum -c md5sums.txt. According to the output of that, they are all ok.

How can I find out for which file the complaint at boot time was?

BTW: When shutting down the computer booted from the persistent live drive, lots of file IO happens in the partition casper-rw. Unfortunately after clicking on the button to really shut down the computer, the screen immediately blanks and only a tiny cursor is in the left upper corner of the screen which might easily get overlooked. It looks like this is when casper-rw is updated. Depending on what one has done before, this "dark phase" before the Ubuntustudio logo with that rotating indicator can take up to one minute! It would be nice to display a warning against pulling out the thumbdrive all the time, when casper-rw is updated! Otherwise the persistent stick is easily ruined.

Adalbert Hanßen
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1 Answers1

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Full Install vs Persistent 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.

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 USB's.

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

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 f.

Full Install Method

A method 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

C.S.Cameron
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