SmallNetBuilder

The Network

With the testbed construction of Part 1 out of the way, I next turned to the task of making sure that my NAS test setup was up to the task of testing 100 MB/s products. Table 1 shows the key components of the current machine that runs iozone and that has been used to produce all test results shown in the NAS Charts to date.

Table 1: Current NAS Test bed iozone computer

The first thing I had to do was to remove the throughput cap that my PCI-based gigabit NIC was imposing by switching to a PCIe-based NIC. Of course, my current NAS testbed machine didn't have the required PCIe X1 slot, so that meant switching to a different machine.

I have only one machine with a PCIe X1 slot, but it already has an onboard gigabit NIC using an Intel 82566DM-2 PCIe gigabit Ethernet controller. The configuration of that Dell Optiplex 755 Mini Tower is shown in Table 2.

Table 2: New NAS Test Bed

I actually did this work for the Gigabit Ethernet NeedTo Know - 2008 where the test setup is fully described. Figure 1 shows a composite of throughput test results for two PCI NICs with no jumbo frames and 4K jumbo frames and two PCIe gigabit NICs without jumbo frames enabled.

Figure 1: Gigabit Ethernet tests w/ PCI and PCIe NICs

The PCI NICs without jumbo frames limit any non-cached NAS test results to about 67 MB/s without jumbo frames and 74 MB/s with 4k jumbo frames. But the PCIe NICs, even without jumbo frames, raises network bandwidth to 113 MB/s. Although this isn't the full, theoretical 125 MB/s of a gigabit Ethernet connection, it should be plenty for the next few years of NAS testing.