Cache Information (Sun Java System Web Server 6.1 SP11 Performance Tuning, Sizing, and Scaling Guide)

Sun Java System Web Server 6.1 SP11 Performance Tuning, Sizing, and Scaling Guide

Cache Information

The cache information section provides statistics on how your file cache is being used. The file cache caches static content so that the server handles requests for static content quickly. For tuning information, seeTuning the File Cache.

Following is an example of how the cache statistics are displayed in perfdump:

CacheInfo:
------------------
enabled             yes
CacheEntries        0/1024
Hit Ratio           0/0 (  0.00%)
Maximum Age         30

enabled

If the cache is disabled, the rest of this section is not displayed.

Tuning

The cache is enabled by default. You can disable it by:

Unselecting it from the File Cache Configuration page under Preferences in the Server Manger.
Editing the FileCacheEnable parameter in the nsfc.conf file. For more information about this file, see the Sun Java System Web Server 6.1 SP11 Administrator’s Configuration File Reference.

CacheEntries

The number of current cache entries and the maximum number of cache entries are both displayed. A single cache entry represents a single URI.

Tuning

You can set the maximum number of cached entries by:

Entering a value in the Maximum # of Files field on the File Cache Configuration page under Preferences in the Server Manger
Creating or editing the MaxFiles parameter in the nsfc.conf file. For more information about this file, see the Sun Java System Web Server 6.1 SP11 Administrator’s Configuration File Reference.

Hit Ratio (CacheHits / CacheLookups)

The hit ratio gives you the number of file cache hits versus cache lookups. Numbers approaching 100% indicate the file cache is operating effectively, while numbers approaching 0% could indicate that the file cache is not serving many requests.

This setting is not tunable.

Maximum Age

This displays the maximum age of a valid cache entry. The parameter controls how long cached information is used after a file has been cached. An entry older than the maximum age is replaced by a new entry for the same file.

Tuning

If your web site’s content changes infrequently, you may want to increase this value for improved performance. You can set the maximum age by:

Entering or changing the value in the Maximum Age field of the File Cache Configuration page in the Server Manager.
Editing the MaxAge parameter in the nsfc.conf file. For more information about this file, see the Sun Java System Web Server 6.1 SP11 Administrator’s Configuration File Reference.