Red Hat DIRECTORY SERVER 7.1, Administrator'S Manual, Page: 464 / 652

Monitoring Database Activity
464 Red Hat Directory Server Administrator’s Guide • May 2005
Database Cache Information Table
The Database Cache Information table provides caching information listed in
Table 12-6.
Database File-Specific Table
The directory displays a table for each index file that makes up your database.
Each of the tables provides the following information:
Table 12-6 Database Performance Monitoring - Database Cache Information
Performance Metric Current Total
Hits Indicates the number of times the database cache successfully supplied a
requested page. A page is a buffer of the size 2K.
Tries Indicates the number of times the database cache was asked for a page.
Hit ratio Indicates the ratio of database cache hits to database cache tries. The closer this
value is to 100%, the better. Whenever a directory operation attempts to find a
portion of the database that is not present in the database cache, the directory
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 performance drops.
To improve this ratio, you can increase the amount of data that the directory
maintains in the database cache by increasing the value of the “Maximum
Cache Size” attribute. See “Tuning Database Performance,” on page 480, for
information on changing this value using the Server Console.
Pages read in Indicates the number of pages read from disk into the database cache.
Pages written out Indicates the number of pages written from the cache back to disk. A database
page is written to disk whenever a read-write page has been modified and
then subsequently deleted from the cache. Pages are deleted from the database
cache when the cache is full and a directory operation requires a database page
that is not currently stored in cache.
Read-only page evicts Indicates the number of read-only pages discarded from the cache to make
room for new pages.
Read-write page evicts Indicates the number of read-write pages discarded from the cache to make
room for new pages. This value differs from Pages Written Out in that these
are discarded read-write pages that have not been modified.