Fedora LiveOS root system and available RAM

Hi to all !

In the Fedora Wiki LiveOS image page it states about Storage :

When a Live CD or Live DVD (a LiveOS image on read-only disc media) is booted, temporary storage is prepared for the system in RAM on each boot by /sbin/dmsquash-live-root in initrd.img, the initial ramdisk filesystem. By default, a 32 GiB, in-memory, copy-on-write, system overlay in a sparse file is prepared (see File Systems below).

I have a harware running with either 16Gb or 32Gb RAM.
In neither case when I boot a Fedora Live OS do I experience this 32 GiB, in-memory, copy-on-write system.

Instead, the root system is around 6.4 GB, with only roughly 1.5GB free space, as stated further :

an apparent 6.4 GiB ext4 root filesystem that has been sparsed and compressed into under 1.6 GiB of actual disc space in the .iso file (or on a LiveOS installed device file system). df -h on an untouched mounting of the root filesystem will report that 4.9G is used and 1.5G is available space out of a total size of 6.4G.

Trying to remount /as in: $ sudo mount / -o remount,70% results in failure.

How can I get the live file system to access all (or most like 70%) of the full RAM available on hardware ?

Thanks !

Playing with ram like that is totally unnecessary for most cases. When booting the live system it uses the available ram as needed and does not require user intervention. This only fails if the ram is so limited as to not be able to properly boot.

I do not understand why you think this would be an issue. Note that the final sentence of that paragraph says: Since the temporary overlay is a sparse file in a tmpfs, a large size, even larger than available memory, may be specified and only what is needed will be allocated as needed.

This means the system sees exactly what is required and allocates only what is necessary (automatically & without user intervention). It may even seem like magic to the uninitiated.

Here is my systematic experience with 8GB/16GB/32GB RAM laptops :

  1. boot the latest Fedora Workstation Live USB
  2. System monitor shows around 1,5GB available space for the root filesystem
  3. Do $ sudo dnf install -y or
    go to getfedora.org and download any .iso image heavier than 2GB

As soon as the required cumulative size of or the download exceeds 1,5/1,8 Gb => the root filesystem is full causing a system freeze.

I would gladly learn how to set the system so that after booting the live USB:

That has nothing to do with ram, and everything to do with free space in the file system.
Running out of space in the root file system has been a cause of freezes and crashes since the very beginning of computers.

What is the output of df?

Are you trying to do a large update or download like that when running the live version with the file system only in RAM and not installed where you have adequate space in the file system for downloads? If so then consider doing the download on a system where you have adequate drive space or use a second usb flash drive that is both mounted and writable as the target for the file being downloaded so you are not restricted to the RAM space for storage.