As Web servers have matured, performance has become increasingly important. Today, with the growth of Web applications for database publishing, content indexing, and collaboration, maximizing hardware and software performance has become a priority. This topic focuses on hardware aspects and makes recommendations for upgrades based on feedback from performance monitoring tests.
Hard disk bottlenecks are most often seen on sites with a very large file set that is accessed randomly. If the bottleneck is the disk access, the percentage of the CPU utilized remains low, the network card is not saturated, but the Physical Disk % Disk Time is high. To improve disk access in this kind of situation, use a redundant array of inexpensive drives (RAID) and striped disk sets. For more information on Physical Disk % Disk Time, see the Windows NT documentation.
CPU bottlenecks are characterized by very high CPU % Utilization numbers while the network card remains well below capacity. If CPU % Utilization is high, you can upgrade the CPU, add additional CPUs to the same computer, or add additional computers on which you replicate your site, and then distribute traffic across them. If you are running other CPU-intensive applications on the Web server, such as a database application, you can move the other applications to another computer. For more information on CPU % Utilization, see the Windows NT documentation.
On a moderately busy site, IIS can completely saturate a 10 Mgb Ethernet card. To prevent the server from becoming network bound, use either multiple 10 Mgb Ethernet cards, or install a 100 Mgb Ethernet or FDDI network card. To check for network saturation, check for CPU % Utilization on both the client and the server. If neither the client or the server is CPU bound, then something else is the problem. Use the Network Monitor agent, included with Windows NT, to check the Network Utilization. If the network is close to 100 percent utilized, for either the client or the server, then most likely the network is the bottleneck. For more information on accessing the Network Monitor, see the Windows NT documentation.
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