zfs-fio KVM testing on Ubuntu 20.04 via the Phoronix Test Suite. volblocksize=128k: Processor: 2 x Intel Xeon Gold 5218R (4 Cores), Motherboard: QEMU Standard PC (i440FX + PIIX 1996) (0.0.0 BIOS), Chipset: Intel 440FX 82441FX PMC, Memory: 16GB, Disk: 215GB QEMU HDD, Graphics: bochs-drmdrmfb, Monitor: QEMU Monitor, Network: Red Hat Virtio device OS: Ubuntu 20.04, Kernel: 5.4.0-72-generic (x86_64), Compiler: GCC 9.3.0, File-System: ext4, Screen Resolution: 1024x768, System Layer: KVM Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 1MB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 1066 |===================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 1MB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 1063 |===================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 4KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 229.3 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 4KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 58588 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 8KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 558.19 |=================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 8KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 71350 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 16KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 950.5 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 16KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 60811 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 32KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 253.6 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 32KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 8118 |===================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 64KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 1506 |===================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 64KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 24105 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 128KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 1269 |===================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 128KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 10156 |==================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 256KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 415 |====================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 256KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 1656 |===================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 512KB - Disk Target: Default Test Directory MB/s > Higher Is Better volblocksize=128k . 573 |====================================================== Flexible IO Tester 3.25 Type: Random Write - Engine: Linux AIO - Buffered: No - Direct: Yes - Block Size: 512KB - Disk Target: Default Test Directory IOPS > Higher Is Better volblocksize=128k . 1142 |=====================================================