ToDo/Block/Qcow2PerformanceRoadmap
The following FFSB benchmark results model QCOW2 performance:
- QCOW2 (2010/9/22) is the upstream QCOW2 code including Kevin's work to avoid flushes when possible.
- QED with L2 Flush is QED with a flush on L2 update, the best QCOW2 can get since a flush is required after refcount update.
- QED is the QED v1 patchset, a fully asynchronous block driver implementation.
All results are throughput in MB/s.
| FFSB Scenario | Threads | QCOW2 (2010/9/22) | QED with L2 Flush | QED |
|---|---|---|---|---|
| Large File Creates (Block Size=256KB) | 1 | 95.1 | 101.0 | 121.5 |
| 8 | 110.0 | 95.2 | 125.0 | |
| 16 | 89.4 | 96.8 | 134.5 | |
| Sequential Reads (Block Size=256KB) | 1 | 68.2 | 154.0 | 149.0 |
| 8 | 262.0 | 849.0 | 817.5 | |
| 16 | 276.0 | 908.0 | 922.0 | |
| Large File Creates (Block Size=8KB) | 1 | 11.8 | 13.9 | 16.3 |
| 8 | 18.4 | 29.7 | 41.0 | |
| 16 | 17.7 | 30.2 | 43.3 | |
| Sequential Reads (Block Size=8KB) | 1 | 20.8 | 26.3 | 22.2 |
| 8 | 13.8 | 136.0 | 131.5 | |
| 16 | 13.8 | 160.0 | 160.0 | |
| Random Reads (Block Size=8KB) | 1 | 3.8 | 3.5 | 3.6 |
| 8 | 13.8 | 26.0 | 25.7 | |
| 16 | 13.7 | 48.8 | 48.4 | |
| Random Writes (Block Size=8KB) | 1 | 22.6 | 22.5 | 22.6 |
| 8 | 14.0 | 113.1 | 112.7 | |
| 16 | 14.0 | 125.2 | 126.7 | |
| Mail Server (Block Size=8KB) | 1 | 7.8 | 8.8 | 8.3 |
| 8 | 10.8 | 45.8 | 46.4 | |
| 16 | 11.8 | 72.0 | 73.2 | |
| Mixed I/O (70% Reads, 30% Writes, Block Size=8KB) | 1 | 10.2 | 9.5 | 8.8 |
| 8 | 24.8 | 63.5 | 62.9 | |
| 16 | 28.6 | 114.1 | 111.9 |
O_DIRECT benchmark execution. Image file on ext4 on LVM on 8 LUNs.