nfs sync enabled qemu testing on Ubuntu 16.04 via the Phoronix Test Suite. nfs sync enabled: Processor: Common KVM @ 3.20GHz (2 Cores), Motherboard: QEMU Standard PC (i440FX + PIIX 1996) (rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org BIOS), Chipset: Intel 440FX- 82441FX PMC, Memory: 1 x 4096 MB RAM QEMU, Disk: 45GB, Graphics: EFI VGA, Network: Red Hat Virtio device OS: Ubuntu 16.04, Kernel: 4.4.0-138-generic (x86_64), Compiler: GCC 5.4.0 20160609, File-System: ext4, Screen Resolution: 800x600, System Layer: qemu nfs sunc enabled: Processor: Common KVM @ 3.20GHz (2 Cores), Motherboard: QEMU Standard PC (i440FX + PIIX 1996) (rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org BIOS), Chipset: Intel 440FX- 82441FX PMC, Memory: 1 x 4096 MB RAM QEMU, Disk: 45GB, Graphics: EFI VGA, Network: Red Hat Virtio device OS: Ubuntu 16.04, Kernel: 4.4.0-138-generic (x86_64), Compiler: GCC 5.4.0 20160609, File-System: ext4, Screen Resolution: 800x600, System Layer: qemu IOzone 3.465 Record Size: 1MB - File Size: 512MB - Disk Test: Read Performance MB/s > Higher Is Better nfs sync enabled . 5318 |==================================================== nfs sunc enabled . 5529 |====================================================== IOzone 3.465 Record Size: 1MB - File Size: 512MB - Disk Test: Write Performance MB/s > Higher Is Better nfs sunc enabled . 87.58 |=====================================================