NAS How To

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.

Component
CPU	Intel 2.4GHz Pentium 4
Motherboard	ASUS P4SD-LA (HP/Compaq custom)
RAM	512 MB DDR 333 (PC2700)
Hard Drives	80GB Maxtor DiamondMax Plus 9 ATA/133 drive with 2MB buffer and NTFS formatted
Ethernet	Intel PRO/1000 MT (PCI)
OS	Windows XP SP2

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.

Component
CPU	Intel Core 2 Duo E4400
Motherboard	Dell Custom
RAM	1 GB DDR2 667
Hard Drives	Seagate Barracuda 7200.10 80GB SATA (ST380815AS)
Ethernet	Onboard (Intel 82566DM-2)
OS	Windows XP SP2

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.