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Re: [Qemu-devel] [RFC PATCH 0/9] vhost-nvme: new qemu nvme backend using
From: |
Ming Lin |
Subject: |
Re: [Qemu-devel] [RFC PATCH 0/9] vhost-nvme: new qemu nvme backend using nvme target |
Date: |
Tue, 01 Dec 2015 21:13:11 -0800 |
On Tue, 2015-12-01 at 11:59 -0500, Paolo Bonzini wrote:
> > What do you think about virtio-nvme+vhost-nvme?
>
> What would be the advantage over virtio-blk? Multiqueue is not supported
> by QEMU but it's already supported by Linux (commit 6a27b656fc).
I expect performance would be better.
Seems google cloud VM uses both nvme and virtio-scsi. Not sure if
virtio-blk is also used.
https://cloud.google.com/compute/docs/disks/local-ssd#runscript
>
> To me, the advantage of nvme is that it provides more than decent performance
> on
> unmodified Windows guests, and thanks to your vendor extension can be used
> on Linux as well with speeds comparable to virtio-blk. So it's potentially
> a very good choice for a cloud provider that wants to support Windows guests
> (together with e.g. a fast SAS emulated controller to replace virtio-scsi,
> and emulated igb or ixgbe to replace virtio-net).
vhost-nvme patches are learned from rts-megasas, which could possibly be
a fast SAS emulated controller.
https://github.com/Datera/rts-megasas
>
> Which features are supported by NVMe and not virtio-blk?
Rob (CCed),
Would you share whether google uses any NVMe specific feature?
Thanks.