Are you guys sure this "dd" method produces accurate results? I ran the following two commands on my FreeNAS system:
dd if=/dev/zero of=tmp.dat bs=2048k count=50k
dd if=tmp.dat of=/dev/null bs=2048k count=50k
The results were as follows:
107374182400 bytes transferred in 694.660328 secs (154570771 bytes/sec)(write)
107374182400 bytes transferred in 722.927058 secs (148526993 bytes/sec)(read)
My system specs are as follows:
SuperMicro MBD-X9SCM-F-O (C204 motherboard)
Intel Pentium G850 (2.9GHz dual core CPU)
Kingston KVR1333D3E9SK2/8G (2x4G DDR3 1333 ECC RAM)
Western Digital WD20EARX (2Tx4 in a RAIDZ-1 configuration)
These benchmark numbers are low considering each drive is capable of 110 MB/s sustained transfer rates. I would expect up to 330 MB/s since the data is striped across three drives with one drive for parity. The next thing I tried is copying 861GB of large files to the ZFS pool and then scrubbing it. The scrub only took 57 minutes. That corresponds to 270 MB/sec which sounds much more reasonable.
dd if=/dev/zero of=tmp.dat bs=2048k count=50k
dd if=tmp.dat of=/dev/null bs=2048k count=50k
The results were as follows:
107374182400 bytes transferred in 694.660328 secs (154570771 bytes/sec)(write)
107374182400 bytes transferred in 722.927058 secs (148526993 bytes/sec)(read)
My system specs are as follows:
SuperMicro MBD-X9SCM-F-O (C204 motherboard)
Intel Pentium G850 (2.9GHz dual core CPU)
Kingston KVR1333D3E9SK2/8G (2x4G DDR3 1333 ECC RAM)
Western Digital WD20EARX (2Tx4 in a RAIDZ-1 configuration)
These benchmark numbers are low considering each drive is capable of 110 MB/s sustained transfer rates. I would expect up to 330 MB/s since the data is striped across three drives with one drive for parity. The next thing I tried is copying 861GB of large files to the ZFS pool and then scrubbing it. The scrub only took 57 minutes. That corresponds to 270 MB/sec which sounds much more reasonable.