SunONE DB Cache Test

Each Directory Server instance has one database cache. The database cache is a pool of memory that holds pages from the database containing indexes and entries.

The size of the database cache is configurable. The cache should be rightly sized in order to prevent/at least minimize expensive and potentially harmful direct disk accesses. With the help of this test, you can monitor how the cache is utilized over time, promptly detect sizing irregularities, and correct them.

Target of the test : A Sun Java System Directory server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for the Sun Java System Directory 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	Refers to the port at which specified host listens to.
DistinguishedName	Represents the server's Distinguished name. This value is to be specified when the server requires explicit authentication of requests. By default, this attribute is set to "none", implying that authentication is not required.
Password	Specify the password to be used for authenticating the request. The password is to be specified whenever the DistinguishedName is not "none".
Confirm Password	Confirm the password (if specified) by retyping it here.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Cache hits	Indicates the number of times the Directory server has successfully processed a search request to retrieve data from the database cache.	Number
Cache tries	Indicates the number of times the Directory server has been looked in to retrieve data from the database cache.	Number
Cache hit ratio	Indicates the ratio of database cache hits to database cache tries.	Percent	The closer this value is to 100%, the better. Whenever a directory operation attempts to find a portion of the database that is not resident in the database cache, the directory server has to perform a disk access to obtain the appropriate database page. Thus, as this ratio drops towards zero, the number of disk accesses increases and directory server performance drops.
Pages read in	Indicates the rate of pages read from disk into the database cache during the last measurement period.	Pages/Sec
Pages written out	Indicates the rate of pages for this file written from cache to disk during the last measurement period.	Pages/Sec	A database page is written out to disk whenever a read-write page has been modified and then subsequently evicted from the cache. Pages are evicted from the database cache when the cache is full and a directory operation requires a database page that is not currently stored in cache.