SWS DNS Cache Test

The DNS cache caches IP addresses and DNS names. The Web Server uses DNS caching for logging and for access control by IP address.

Using this test, you can determine whether the DNS cache is enabled or not, and if so, how effectively the web server instance has been using it.

Target of the test : An Oracle iPlanet Web Server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for the Oracle iPlanet web server instance being monitored.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed.

Host

The host for which the test is to be configured.

Port

The port number at which the specified Host listens to.

User

Specify the name of the administrator of the administration server to which the target web server is registered.

PasswdFile

The eG agent connects to the administration server to which the target web server is registered to extract the required metrics. To enable the eG agent to communicate with this administration server, you first need to create a password file containing the administrator password for accessing the server; this password file should be created in the install directory of the web server. Specify the name of this file in the PasswdFile text box; by default, this is admin.passwd.

AdminServer

Specify the IP address of the administration server to which the target web server is registered.

AdminPort

Indicate the port at which the administration server listens.

Config

In Web Server 7.0, all configurable elements of a server instance like web applications, configuration files, and search collection indexes are logically grouped and termed as a Configuration. To enable the test to locate the web server instance to be monitored, you need to mention the Configuration that applies to the instance. In the Config text box therefore, specify the name of the Configuration which the target web server instance uses.

Node

Node is a network resource, such as a server or a host. Instance refers to the environment of a web server daemon on a given node, including its configuration, log files and other runtime artifacts such as lock databases, caches and temporary files. To enable the test to identify the exact web server instance to be monitored, you need to specify the name of the Node on which the instance executes. The test will thus monitor only that web server instance that operates on the given Node and which uses the specified Config.

SSL

Set this flag to Yes if the administration server is SSL-enabled; if not, set it to No.

WebServerDir

Here, specify the Oracle iPlanet web server installation directory.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

No of cache hits

Indicates the number of times the DNS cache was successfully looked up for an IP address.

Number

 

No. of cache misses

Indicates the number of times an IP address  was not found in the cache.

Number

This number includes newly-accepted connections and connections from the keep-alive system.

Hit ratio

Indicates the number of cache hits compared to the number of cache lookups.

Percent

Ideally, the value of this measure should be high. A low value is indicative of too many cache misses. This could be owing to a badly sized cache.

Typically, the cache should be as large as the maximum number of clients that access your web site concurrently.

Note that setting the cache size too high wastes memory and degrades performance.

Async lookup enabled

Indicates whether the server uses its own asynchronous DNS resolver instead of the operating system's synchronous resolver.

Boolean

 

Lookups in progress

Indicates the current number of lookups in progress.

Number

 

Async name lookups

Indicates the number of times during the last measurement period DNS names were looked up in the cache, so that the corresponding IP addresses could be resolved.

Number

 

Async address lookups

Indicates the number of times IP addresses were looked up in the cache, so that the corresponding DNS name could be identified.

Number

 

DNS cache enabled

Indicates whether the cache is enabled or not.

Boolean