MACROMEDIA COLDFUSION MX-CLUSTERCATS Bedienungsanleitung PDF herunterladen (Seite 27)

Successful scalability implementations 17

• Network connectivity and bandwidth — consider the type of network your

application will run on (LAN/WAN/Internet) and how much traffic it typically

receives. If traffic is consistently heavy, you may need to add additional nodes,

routers, switches, or hubs to the network to handle the increased traffic.

• Databases — database access, while vitally important to your application’s capabilities

and feature set, can be costly in terms of performance and scalability if it is not

engineered efficiently. When creating data sources for accessing your database, use a

native database driver rather than an ODBC driver, if possible, because it will provide

faster access. Similarly, try to reduce the number of individual SQL queries that must

be repetitiously constructed and submitted, by placing common database queries in

stored procedures that reside on the database server. Tune your databases and queries

for maximum efficiency.

DNS effects on website performance and availability

Improper Domain Name System (DNS) setup and configuration on web servers is one of

the most common problems administrators encounter. This section addresses the

following topics:

• “What is DNS?” on page 17

• “DNS effects on site performance and availability” on page 17

• “DNS core elements” on page 18

What is DNS?

DNS is a set of protocols and services on a TCP/IP network that allows network users to

use hierarchical natural language names, rather than computer IP addresses, when

searching for computer hosts (servers) on a network. DNS is used extensively on the

Internet and on private enterprise networks, including LANs and WANs.

The primary capability of DNS is its ability to map host names to IP addresses, and vice

versa. For example, suppose the web server at Macromedia has an IP address of

157.55.100.1. Most people would connect to this server by entering the domain name

(www.macromedia.com), not the less-friendly IP address. Besides being easier to

remember, the name is more reliable, because the numeric address could change for a

variety of reasons, but the name can always be reserved.

DNS effects on site performance and availability

Internet DNS is a powerful and successful mechanism that has enabled huge numbers of

individuals and organizations to create easily locatable websites on the Internet. However,

DNS by itself may not allow your website to perform and scale as it should, thus causing

it to become unavailable and unreliable. Whether you use DNS by itself to load balance

inbound traffic depends largely on the site’s purpose and the amount of concurrent

activity you expect on it. For instance, a low-volume, static site that provides only textual

HTML information can probably be accommodated by round-robin DNS. However, a

high-volume, dynamic, e-commerce site that you anticipate doing lots of volume won’t

perform or scale well if it is only supported by round-robin DNS.

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MACROMEDIA COLDFUSION MX-CLUSTERCATS Bedienungsanleitung Seite 27