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Notes

QEMU Storage Performance

Comparing the emulated SATA and VirtIO, the VirtIO disk comes out massively faster.

Host machine is Debian on Intel Skylake with Samsung PM951 NVMe SSD.

It looks like IO speed might be CPU latency bound, since setting the virtual disk caching mode to unsafe doesn’t really improve the performance by much.

With the virtio disk caching set to “unsafe”, where it ignores guest sync requests.

Reference Performance of the underlying Samsung PM951 NVMe

https://www.samsung.com/us/labs/pdfs/collateral/sm951-prodoverview-0615-v1.pdf

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