13 Tips for Optimizing Internet Information Server

Whether you administer a small, corporate intranet or a high-bandwidth Internet site, knowing how to optimize Microsoft's Internet Information Server (IIS) Web server software can affect the success of your project. Microsoft released IIS 1.0 in early 1996 as an add-on to Windows NT Server 3.51. Since version 1.0, IIS has grown into a stable, scalable environment for intranet and Internet Web-serving. NT ships with IIS 2.0. (For more information about IIS 2.0, see Stephen Genusa, "Serving Up Internet Information," October 1996, and the Windows NT Magazine Lab's "Web Server Software Roundup," September 1996.) Microsoft recently released IIS 3.0, which includes the Active Server Pages execution environment that lets you run ActiveX Scripts and ActiveX Server Components on the server. You can download IIS 3.0 from Microsoft's Web site at http://www.microsoft.com/iis. Although much of IIS is self-tuning, the product provides configuration options that you can use to tune IIS for maximum throughput. Most IIS configuration options are available through the IIS administrative interface, Internet Service Manager, but some require changes to the NT Registry. Let's look at several tips for optimizing IIS performance.

Tip 1:
Choose the Right Server Hardware and Configuration
Pentium-based servers will perform well as IIS servers. IIS runs on MIPS, PowerPC, and Alpha processors, but these machines are more expensive, and Intel versions usually are released before other platforms' versions.

Determining the proper amount of memory depends on what other applications you plan to run on the server. If IIS is the only application, 32MB is probably enough memory. However, if you plan to run other applications such as SQL Server or connect to other databases via Open Database Connectivity (ODBC), you'll need a minimum of 64MB of memory for optimal performance. Disk space will vary depending on the size of your Web site. After installing IIS, you can use NT's Perfmon to help determine the proper hardware requirements to locate any bottlenecks in the system, such as processor utilization, network throughput, and disk access times.

Tip 2:
Use Fast Internet Connections
As with any Web server, IIS's performance depends heavily on the speed of your Internet connection. To attach your site to the Internet, an Internet Service Provider (ISP) provides you with a network cable. In the US, these leased connections vary in speed from 56Kbps (with Integrated Services Digital Network--ISDN--or Frame Relay) to 45Mbps (with a T3 connection). Small IIS sites need at least an ISDN Basic Rate Interface (BRI--64Kbps to 128Kbps) on an Ethernet or Token-Ring backbone. Anything less than ISDN on even a small site with a couple of users will quickly consume all your bandwidth and slow download times to a crawl. Large sites, such as Microsoft's, have up to eight 45Mbps T3 lines on 100Mbps Fiber Distributed Data Interface (FDDI) backbones to support millions of daily connections.

Tip 3:
Set Up the System as a Standalone Server
When you install NT Server, you can designate it as a Primary Domain Controller (PDC), Backup Domain Controller (BDC), or standalone server. For maximum IIS performance, set up your IIS server as a standalone server dedicated to performing only IIS functions, so it doesn't use additional system resources to perform network logon requests. If you have multiple servers, let the server participate in a domain but not as a domain controller. This way, you can distribute user accounts among the servers in the domain for easier access control and administration.

Tip 4:
Use NT Server's DNS Round-Robin Feature
A great addition to NT Server 4.0 is the new Domain Name System (DNS) service. The graphical interface will shave hours off setting up a new DNS server and let you manage multiple servers from one interface. To help your site accommodate future processing needs and increasing Internet/intranet traffic, NT's DNS service performs a round-robin function. An administrator can add a series of identical A (host) records in Domain Name Service Manager to create a pool of addresses pointing to different physical servers. This virtual router approach lets you distribute the processing and traffic load across multiple servers, while providing a fault-tolerant environment in case one server fails.

To create a round-robin pool, add new host records ( i.e., www and ftp records) in NT's Domain Name Service Manager for each server and IP address. Screen 1 shows a sample round-robin pool. After adding the records, you can use the ping command with the host name to display an alternating pool of addresses (more about ping in Tip 11).

When you use the round-robin approach to distribute network traffic across multiple servers, you also face synchronizing the peer servers' content. Content is the data available on your IIS server and can include HTML, FTP, or Gopher files. Synchronization methods include using FTP, batch processing, or directory replication to distribute the same content to your Web servers. Microsoft's latest NT content-distribution solution is the Content Replication System, which is part of Microsoft's Com-mercial Internet System (CIS­previously Normandy). CIS is a suite of applications including Conference Server, Personalization System, and Merchant Server. Designed as a fault-tolerant, scalable solution, the Content Replication System can distribute and synchronize data across a range of network sizes--from small LANs to large global information networks with dozens of distribution servers. Microsoft plans to release the Content Replication System in the second quarter of this year. You can find more information about it and other CIS components at http://www.
ms-normandy.com/.