OVFS, OpenDAL File System via Virtio

OVFS is a backend implementation of VirtioFS. It provides a filesystem interface for VMs based on OpenDAL, aiming to accelerate VMs IO performance by VirtIO and seamlessly connect with various storage backends.

How to Use

The following components are required:

• Rust environment on the host to run OVFS.
• QEMU 4.2 or later for built-in VirtioFS support.
• A Linux 5.4 or later guest kernel for built-in VirtioFS support.

Install QEMU and VMs

$ sudo apt-get install qemu qemu-kvm -y # debian/ubuntu

Download and install the VM, taking Ubuntu as an example:

$ wget https://releases.ubuntu.com/20.04/ubuntu-20.04.6-live-server-amd64.iso
$ truncate -s 10G image.img
$ sudo qemu-system-x86_64 -enable-kvm -smp 2 -m 4G \
    -cdrom ubuntu-20.04.6-live-server-amd64.iso \
    -drive file=image.img,format=raw,cache=none,if=virtio \
    -no-reboot -boot d

Mount shared directory on VMs

Run OVFS and set the listening socket path and service configuration used:

host# cargo run --release <socket-path> <backend-url>

backend-url is the URL that includes the scheme and parameters of the service used, in the following format:

- fs://?root=<path>
- s3://?bucket=<bucket>&endpoint=<endpoint>&access_key_id=<access-key-id>&secret_access_key=<secret-access-key>&region=<region>

Run the VM through QEMU and create a VirtioFS device:

host# sudo qemu-system-x86_64 --enable-kvm -smp 2 \
    -m 4G -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on -numa node,memdev=mem \
    -chardev socket,id=char0,path=<socket-path> -device vhost-user-fs-pci,queue-size=1024,chardev=char0,tag=<fs-tag> \
    -drive file=image.img,format=raw,cache=none,if=virtio \
    -boot c

Mount a shared directory in the VM:

guest# sudo mount -t virtiofs <fs-tag> <mount-point>

Notes: For more examples or some useful Ubuntu unattended autoinstall scripts, see the scripts here.

Periodic Reports During GSoC 2024 and Acknowledgements

The following are reports from the implementation phase, all synchronized in the OpenDAL dev mailing list.

• 05.12-05.19
• 05.20-06.02
• 06.02-06.27
• 06.28-07.22
• 07.23-08.04
• 08.05-08.20

We extend our gratitude to the virtiofsd project for its contributions; OVFS primarily references the implementation of virtiofsd v1.10.0. Special thanks to Xuanwo and Manjusaka for their guidance throughout the project.