Enter, the VelociRaptor
Since in Part 2, I had reached the "It's the Drive, Stupid!" conclusion, I contacted Western Digital who kindly provided a few of their WD3000HLFS VelociRaptor drives, which are, according to WD, "The Fastest SATA Drive in the Known Universe".
The VelociRaptor is the second generation of WD's "Raptor" line, which are all based on 10,000 RPM 2.5" drive mechanisms. For the 3.5" models, the 2.5" drive is ensconced in a heatsink / frame dubbed the "IcePack" (Figure 3).
Figure 3: WD VelociRaptor
A quick check with Simpli Software's HD Tach confirmed a > 100 MB/s average read transfer rate (Figure 4).
Figure 4: VelociRaptor HD Tach results
Figure 5 adds two test runs with the VelociRaptors to the tests shown in Figure 2. (I removed the TS-509 Pro, PCI run to reduce chart clutter.)
So we now have:
- 2 GB - NAS configured as in Table 1, with 2 GB of memory
- 1 GB - Same as #1, but with NAS memory reduced to 1 GB
- TS-509Pro, 1x1TB - QNAP TS-509 Pro with a single 1 TB drive
- 1GB, VRaptor - NAS memory @ 1 GB, iozone memory @ 512 MB
- 1GB, VRaptor, 4kjum - same as #4, but w/ 4k jumbo LAN connection
The interesting thing in this graph is that the VelociRaptor doesn't improve write performance until we hit the 2 GB non-cached test. But there, it keeps performance up near 80 MB/s, while the Seagate drive drops off to around 51 MB/s. Note also that using 4k jumbo frames actually reduced performance.
Figure 5: Write Performance Comparison w/ VelociRaptor
Read performance (Figure 6) shows that the VelociRaptor has some value-add. Throughput drops only to 51 MB/s for the 2 GB file size, while the Barracuda sinks to 15 MB/s when caching stops. But there is still no performance improvement for most of the file sizes—the "Wall" remained intact.