MACROMEDIA ClusterCATS, Руководство пользователя

Страница: 30 / 156

20 Chapter 2 Scalability and Availability Overview
The DNS entries would look like the following:
:
To ensure that your site lookups and translations occur as intended, you must provide
correct entries in your DNS records, as shown. Also, to enable round-robin DNS
functionality, you must create round-robin entries as shown.
On the Windows platform, you make DNS entries using the Domain Name Service
Manager utility.
On UNIX platforms, you make DNS entries in the name.db file, which is read by the
DNS server’s Berkeley Internet Name Daemon (BIND).
Load testing your web applications
Load testing is the process of defining acceptable benchmarks for your web application’s
performance, and then simulating load and measuring resulting response times and
throughput against the benchmarks. You perform load testing to measure the
application’s ability to scale.
This section discusses the following topics:
•
“Reasons to perform load testing” on page 20
•
“How to load test your web applications” on page 21
•
“Load-testing considerations” on page 22
Reasons to perform load testing
Load testing is important to your website’s success because it lets you test its capacities
before you deploy it, so you can find and fix problems before they are exposed to your
users. Determining your site’s purpose, and the amount of traffic you anticipate, may
affect how you load test it.
Managers of small sites, who don’t expect heavy concurrent loads, might be able to
organize actual users to simultaneously access the site to perform load testing. However,
this is difficult to accomplish well, because it introduces many human variables. In fact,
for larger business-critical systems that expect heavy concurrent load, this type of testing
is not feasible and does not provide satisfactory or realistic results.
A better approach to load testing is to use load simulation software. There are some
excellent software load-testing tools on the market that let you simulate heavy loads
; Entries for forward-resolution: A-records
www1.yourcompany.com IN A 192.168.0.1
www2.yourcompany.com IN A 192.168.0.2
; Entries for reverse-resolution: PTR-records
192.168.0.1 PTR www1.yourcompany.com
192.168.0.2 PTR www2.yourcompany.com
; Round Robin entries
www.yourcompany.com IN A 192.168.0.1
www.yourcompany.com IN A 192.168.0.2