ramroot is currently not working with any kernel 5.10+.
During early system boot, the ramroot initcpio hook determines the host machine's total ram and prompts the user y/n to load the root file system to zram if enough space is available.
A ramroot helper script easily enables/disables and/or generates additional ramroot config files.
This package is available in the AUR for easy installation. A basic config file is created during initial installation.
- Arch Linux
- ramroot is designed specifically to work with the Arch Linux boot process. These scripts work with slight modifications on other distributions from time to time, however this not officially supported
- A dependency of the linux package. This is included here as linux is no longer included in the Arch Linux base package set.
This file is an ash shell script. Many common bash builtins are not available here and the syntax tends to be a bit stricter. The fallback config file can be viewed at /usr/lib/ramroot/ramroot.conf.
After any changes are made to /etc/ramroot.conf, a user must
ramroot -E or
mkinitcpio -P in order for those changes
to be built into a new initramfs image.
All UUID (or PARTUUID) values must include the proper
prefix. A mountpath is an absolute mount path (as given in
/etc/fstab). Every size is a whole number of mebibytes
- Defines additional mounts to load to zram during initramfs. A mount consists of the UUID separated from the mountpath by a colon. Multiple mounts are separated by spaces or newlines.
- Defines mounts to specifically ignore by ramroot. The
UUID is optional for these mounts. These will not
be loaded to zram or mounted normally. If / is specified in
mounts_null, ramroot will skip loading altogether.
- Default zram y/n prompt value. Valid values are yes or no.
- Boot prompt timeout, positive integer between 1 and 33. After
this many seconds, the zram y/n prompt will assume
- Minimum amount of free ram required.
- Minimum amount of free zram required. If both this and
ram_mincannot be satisfied, the boot prompt automatically selects no.
- Preferred amount of free ram. If both
zram_minare satisfied, additional memory is allocated to ram up to this preferred ram value.
- Maximum amount of free zram to create. Once
ram_prefis satisfied, the amount of free zram is further extended to
All remaining memory is allocated towards ram.
The structure of this directory mirrors the hierarchy of the root file system. Upon a successful sync to zram, any files and directories contained in /etc/ramroot/ are non-persistently overwritten to the root directory.
This can be used to load any number of custom scripts, binaries, configs, etc when boot from zram. Just a few use case examples for this include: a custom zram hostname at /etc/ramroot.z/etc/hostname, enable autologin when boot from zram via a /firstname.lastname@example.org/override.conf file, or even add more sudo access with drop in files in /etc/ramroot.z/etc/sudoers.d/.
Any files copied from /etc/ramroot/ to / in this manner preserve all ownerships. Also note that symbolic links (rather than their target files) will be overwritten by this action (due to the fact that they aren't resolved yet during early initramfs).
Any files contained within a .ramroot.z directory in a user's home folder are non-persistently overwritten to their home folders upon a sync to zram as above.
- Attempt to detect the root file system partitions and generate a new config file.
- Remove ramroot hook from /etc/mkinitcpio.conf and rebuild initramfs image.
- Add ramroot hook to /etc/mkinitcpio.conf and rebuild initramfs image.
-o, --output <FILE>
- Save new config to FILE instead of /etc/mkinitcpio.conf.
- Overwrite output files without asking.
- Display help text and exit.
The file system transfer to ram takes several minutes. As soon as the boot process is complete, the boot media can be safely removed.
Remember that all changes to files in ram are completely lost when the host machine is power cycled. To persistently update the system and edit files, boot the device without transferring the filesystem to ram.
Keep a clean and trimmed down system to maintain faster zram sync times. Arch Linux stores downloaded packages in /var/cache/pacman/pkg/. After every update, if no problems occur, consider removing old packages.
Also, keep in mind that higher quality (more expensive) USB flash drives often exhibit a dramatic improvement in zram sync times.