RedoxFS

This is the default filesystem of Redox OS, inspired by ZFS and adapted to a microkernel architecture.

Redox had a read-only ZFS driver but it was abandoned because of the monolithic nature of ZFS that created problems with the Redox microkernel design.

(It's a replacement for TFS)

Current features:

Compatible with Redox and Linux (FUSE)
Copy-on-write
Data/metadata checksums
Transparent encryption
Standard Unix file attributes
File/directory size limit up to 193TiB (212TB)
File/directory quantity limit up to 4 billion per 193TiB (2^32 - 1 = 4294967295)
Disk encryption fully supported by the Redox bootloader, letting it load the kernel off an encrypted partition.
MIT licensed

Being MIT licensed, RedoxFS can be bundled on GPL-licensed operating systems (Linux, for example).

Tooling

RedoxFS tooling can be used to create, mount and edit contents of an .img file containing RedoxFS. It can be installed with:

cargo install redoxfs

If you found errors while installing it make sure to install the libfuse 3.x package for your Unix-like distribution.

Create a disk

You can create an empty, non-bootable RedoxFS by allocating an empty file with fallocate then run redoxfs-mkfs to initialize the whole image as RedoxFS.

fallocate -l 1G redox.img

redoxfs-mkfs redox.img

To create an encrypted disk use the --encrypt option, it will ask the password through a masked prompt:

redoxfs-mkfs --encrypt redox.img

To create a disk with contents from an existing directory use redoxfs-ar (currently the redoxfs-ar tool overwrites existing content and have no --encrypt option).

redoxfs-ar redox.img ./sysroot

The second option of redoxfs-mkfs and third option of redoxfs-ar tools accepts a file that contains a raw image to be written as reserved disk space. This is meant to be a bootloader. Redox is booted using the official bootloader.

First you need to download the bootloader repository and build it, the following commands will build a BIOS bootloader:

git clone https://gitlab.redox-os.org/redox-os/bootloader

make -C bootloader TARGET=x86-unknown-none BUILD=build all

Once the bootloader is available at bootloader/build/bootloader.bin after compilation, you can create a new bootable disk using either redoxfs-mkfs or redoxfs-ar:

redoxfs-mkfs redox.img bootloader/build/bootloader.bin

redoxfs-ar redox.img ./sysroot bootloader/build/bootloader.bin

You can also convert a non-bootable disk into bootable using redoxfs-clone:

redoxfs-clone redox.img redox-bootable.img bootloader/build/bootloader.bin

It's not possible to create a bootable UEFI using this option because it creates a GPT-partitioned disk, which currently is only implemented in redox-installer. A dual boot option in the same disk is also impossible if booting from a BIOS firmware.

Note that you need to have boot/kernel and boot/initfs in the image to make it actually bootable. You can build those from the main build system or the kernel and base repositories.

Mount a disk

To mount the disk run the redoxfs [image] [directory] command, for example:

mkdir ./redox-img

redoxfs redox.img ./redox-img

It will mount the disk using FUSE underneath.

The difference is that redoxfs-ar overwrites existing disk content. Mounting a disk through FUSE is the only way to update existing content in the RedoxFS-formatted image.

Unmount the disk

Unmount the disk using FUSE unmounting tool:

fusermount3 ./redox-img

Extend the disk

⚠️ Warning: Experimental, please backup before

To extend an existing disk, you need to extend the file before:

truncate -s 2GB redox.img

Then you can run the redoxfs-resize [disk] [size] command. The [size] option can be max (the default), min, or a fixed size defined in the parse-size library.

redoxfs-resize ./redox.img

minimum size: 438.75 MB (418.42 MiB)
maximum size: 2.00 GB (1.86 GiB)
new size: 2.00 GB (1.86 GiB)
growing by 1559135232
redoxfs-resize: resized filesystem on redox.img
	uuid: febb081e-06ff-4786-a878-f1bb031cdf97
	size: 2.00 GB (1.86 GiB)
	used: 438.65 MB (418.33 MiB)
	free: 1.56 GB (1.45 GiB)

Shrink the disk

⚠️ Warning: Experimental, please backup before

To shrink an existing disk you can use the redoxfs-resize tool:

redoxfs-resize ./redox.img min

minimum size: 438.77 MB (418.44 MiB)
maximum size: 2.00 GB (1.86 GiB)
new size: 438.77 MB (418.44 MiB)
shrinking by 1559135232
redoxfs-resize: resized filesystem on redox.img
	uuid: febb081e-06ff-4786-a878-f1bb031cdf97
	size: 438.77 MB (418.44 MiB)
	used: 438.64 MB (418.32 MiB)
	free: 122.88 kB (120 KiB)

You can use the value from "shrinking by ..." to accurately tell how much bytes can be shrinked:

truncate -s -1559135232 redox.img

The Redox Operating System