Low-Cost Network Area Storage Devices: Page 9 of 17

We tested network-attached storage devices with Iometer 2003.5 10, SourceForge's tool for measuring and characterizing I/O subsystems. Our Green Bay, Wis., Real-World Labs test bed included 10 2.4-GHz Pentium 4 client machines, as well as an Extreme Networks Summit7i switch and a Cisco Catalyst 6500 with a copper Gigabit Ethernet card. Five machines were hooked to our north subnet and five to our south subnet. The NAS devices were attached to the north subnet with eth0 and to the south subnet with eth1, if the machine had two ports. An eleventh PC, hooked to the north subnet, served as a console for Iometer.

Our Iometer tests gauged CIFS (Common Internet File System) performance and NFS (Network File System) performance.

On the CIFS side, we performed the following tests: 64-Kbps linear read test; 64-Kbps linear write test; 1-MB linear read test; 1-MB linear write test; 2-MB linear read test; 2-MB linear write test; CIFS IOps and NWC CIFS Generalized Custom Test.

For all linear read and write tests, we set the read/write distribution to 100 percent read for the read tests and 100 percent write for the write tests. Random/sequential distribution was set at 100 percent sequential. Our CIFS IOps test had a 512-byte transfer request size, and was also set to 100 percent read and 100 percent sequential.

The NWC CIFS Generalized Custom Test had transfer request sizes of 512 bytes with 33 percent access distribution, 2 KB with 34 percent access distribution and 64 Kbps with 33 percent access distribution. On the 512-byte segment, the percent read/write distribution was set at 100 percent read and the percent random/sequential distribution at 100 percent sequential. The 2-KB segment had a 67 percent read and 33 percent write distribution and the percent random/sequential was set at 100 percent random. On the 64-Kbps segment, we set the percent read/write distribution to 100 percent read and the percent random/sequential distribution to 100 percent read.