liveroot-snix

Initcpio hooks for non-persistent boot. A fork of liveroot with ZFS support, improved compression options, and a cleaner codebase.

How it works

At boot, liveroot intercepts the root mount and overlays it with a RAM-backed device, so all writes go to RAM instead of disk. The original disk is never modified during the session.

Modes

Kernel cmdline	Description
oroot=raw	tmpfs overlay — no compression, fastest
oroot=compressed	zram overlay with compression
oroot=live	full copy of root into zram — slowest boot, fastest runtime

Installation

Install via the PKGBUILD:

makepkg -si

Setup

1. Add to MODULES in /etc/mkinitcpio.conf:

   MODULES=(zram ext4 overlay)
   

2. Add oroot to HOOKS in /etc/mkinitcpio.conf — after udev, and after zfs if using ZFS:

   HOOKS=(base udev zfs oroot ...)
   

3. Add the desired mode to your bootloader kernel cmdline:

   oroot=compressed
   

4. Rebuild the initramfs:

   mkinitcpio -P
   

Configuration

Edit /etc/liveroot.conf to set defaults:

# compression algorithm for oroot=compressed and oroot=live
# valid: lzo lzo-rle lz4 lz4hc zstd deflate 842
OROOT_ALGO=zstd

# fstab entries to keep active when using oroot=live
# exact match: /home
# prefix match: /home*  (matches /home, /home/user, ...)
# / is always kept regardless of this setting
OROOT_FSTAB_KEEP="/"

Any option can be overridden per-boot on the kernel cmdline:

oroot=compressed oroot_algo=lz4

ZFS

liveroot-snix supports ZFS root out of the box. Use the standard root=ZFS=pool/dataset syntax on the kernel cmdline. The zfs hook must appear before oroot in the HOOKS array.

Differences from upstream

• ZFS root support
• Replaced LZO compression with zstd (configurable)
• Replaced ext2 with ext4 (no journal) on zram devices
• Configurable per /etc/liveroot.conf with per-boot cmdline overrides
• fstab entries are automatically commented out in oroot=live mode to prevent systemd from remounting datasets from disk
• Removed overlay_flush script
• Removed compiler script