Results for the iozone benchmarks are shown in Figures 4 - 7.
Figure 4: RAID 0 Throughput comparison - write
RAID 0 writes are very similar at the 1 GB and higher file sizes while RAID 0 reads are similar across all file sizes shown.
Figure 5: RAID 0 Throughput comparison - read
Performance tracks pretty well at smaller and largest file sizes, but with a bit more spread at the largest file sizes.
Figure 6: RAID 1 Throughput comparison - write
Read performance is again pretty similar, except for the Samsung drive at the 1 GB and higher file sizes.
Figure 7: RAID 1 Throughput comparison - read
My take-away from the iozone tests is that the performance with the 2.5" drive is more similar than different from that with the 3.5" drives installed.
So I learned that it was just my ignorance about today's higher-performance 2.5" SATA drives that was making me think that using them (or at least drives performing equal to or better than the WD Scoripo Black) would sacrifice performance.
But I wasn't surprised that using 2.5" drives would yield lower power consumption. But Table 1 shows a 40% reduction from the 35W drawn by two Seagate 7200.11s to the 20W consumed by the pair of WD Scorpio Blacks!
|Drives spun down (W)||18||20||20|
Table 1: Power Consumption
The final benefit from using the 2.5" drives is their virtually silent operation! They were so quiet, that I had to rely on the TS-239 Pro's front panel lights to know whether they were spun down or up.
The only disadvantage that I can see from using a 2.5" NAS is that you won't get as much storage for your buck and total capacity will be lower. The largest 7200 RPM 2.5" SATA drive as I write this is the 500 GB Seagate Momentus 7200.4 (ST9500420AS), while the largest 3.5" SATAs are 2 TB.