Flashybrid is a simple tool to help setting up and managing hybrid flash/disk/ram based Debian systems (including Raspbian). The system can use a small flash disk as root filesystem and run off of ramfs. Typical use cases include routers and other embedded systems with SD, CF or other small flash-based storage.
The main purpose of this tool is to enable a system to run off of a readonly filesystem. This has several advantages, such as ensuring consistent system state across hard resets (e.g. power loss), or drastically reducing write operations to flash devices (which have a finite number of sustainable write cycles).
To use this package, you will need a 2.4 or greater version of the Linux kernel, with tmpfs support builtin.
Flashybrid has apparently been abandoned by its upstream authors, and as I use it regularly, I decided to take over maintainership. Note that I use it almost only with single-partition setups, so it’s better tested in that context. Support for multi-partitions on best-effort basis.
GPLv2 or later
Source and architecture-independant packages are available:
From 0.19, flashybrid is compatible with Jessie (systemd). 0.21 makes it more friendly toward systems with multiple mountpoints. 0.22 adds a native systemd service file which restores compatibility with Stretch. 0.23 ensures no filsystem boundary is crossed when syncing ram filesystem.