[kata-dev] [Announce] virtio-fs released with Kata Containers support

Qixuan Wu qixuan.wu at linux.alibaba.com
Sun Dec 16 01:09:48 UTC 2018

Hi Stefan,

Very good news. Seems data is much better than 9pfs.

And I have some doubt, it's better if they can be answered:
1) Did you compare the performance to the virtio-blk raw or qcow2 
solution of normal virtual machine?
2) Whether does it impact live-migration of guest os ?

Anyway, it's a major step. Thank you Stefan.

Qixuan Wu

On 2018/12/11 AM 3:25, Stefan Hajnoczi Wrote:
> Dear Kata Containers Community,
> I'm delighted to announce the first release of virtio-fs, a new shared
> file system for virtual machines that is designed for container use
> cases, including shared volumes.
> Unlike virtio-9p and NFS over AF_VSOCK, virtio-fs aims to take advantage
> of the co-location between the virtual machine and the hypervisor in
> order to achieve local file system semantics and improve performance.
> For example, it can use Linux Direct Access (DAX) to access file
> contents directly from the host page cache.  This reduces communication
> with the file server and avoids duplicating data into each sandbox VM.
> It also means that mmap MAP_SHARED on a shared volume is coherent
> between sandbox VMs.
> The Linux kernel code (including performance numbers) has been posted
> here:
> https://marc.info/?l=linux-fsdevel&m=154446243324255&w=2
> Kata Containers integration is already available so you can benchmark
> and test virtio-fs.  The project is under active development and we
> still expect to make significant changes based on feedback and
> collaboration.
> We hope virtio-fs is interesting as a next step in overcoming
> virtio-9p's performance and limitations.  Let us know how it performs!
> You can read more about virtio-fs here:
> https://virtio-fs.gitlab.io/
> The Kata HowTo is here:
> https://virtio-fs.gitlab.io/howto-kata.html
> The Kata runtime and agent changes are fairly straightforward and
> comparable to virtio-9p.  There are several other code changes due to
> using a Fedora initramfs, systemd, and modular kernel.  These are not
> essential to virtio-fs but are simply how I preferred to develop and
> test.
> The FAQ on the virtio-fs website explains the main technical features.
> Please let me know if you have any questions or need help getting it
> running!  I'm also on #kata-dev IRC if you need a hand.
> Stefan

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