Content Server Disk Cache Hits Test

Direct disk accesses are expensive operations, which may result in increasing the processing overheads and eventually, degrading the overall performance of the database server. The primary focus of administrators therefore is to improve the disk cache usage, so that direct disk accesses are kept at a minimum. By closely monitoring the requests to the Content Server and reporting the fraction of requests that have been serviced by the disk cache, this test reveals whether/not the disk cache has been effectively utilized and helps assess the impact of this usage on the processing overheads of the server. From the metrics reported by this test. administrators can also figure out if the disk cache needs any further fine-tuning. 

Target of the test : A Teratext Content Server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for the Teratext Content server 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

User, Password, Confirm Password

To monitor the Content Server, the eG agent should connect to the server using the credentials of a user with rights to access the IR-EXPLAIN-1database. Provide the credentials of such a user in the User and Password text boxes, and confirm the password by retyping it in the Confirm Password text box. 

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Hits

Indicates the number of requests serviced by the disk cache during the last measurement period.

Number

A high value is desired for this measure.

Misses

Indicates the number of requests that were not serviced by the disk cache during the last measurement period.

Number

A low value is desired for this measure.

Hit ratio

Indicates the percentage of requests that were serviced by the disk cache.

Percent

A high ratio of hits is ideal. A very low ratio indicates that a majority of requests have been served by direct disk accesses only. This has an adverse impact on the overall health of the database server.