Sun Microsystems Sun Java System Web Server 7.0, Руководство пользователя

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Tuning
Higher hit ratios result in better performance. To maximize the hit ratio, see the tuning
information for
“Acceleratable Responses” on page 61 .
File Cache Enabled
If the cache is disabled, the rest of this section is not displayed in
perdump
. In the Admin
Console, the File Cache Statistics section shows zeros for the values.
Tuning
The cache is enabled by default. You can disable it in the Admin Console by deselecting the File
Cache Enabled box on the configuration's Performance tab
⇒
Cache sub tab, under File Cache.
To disable it using the command-line-interface, use
wadm set-file-cache-prop
and set the
enabled
property to false.
File Cache Entries
The number of current cache entries and the maximum number of cache entries are both
displayed in
perfdump
. In the Admin Console, they are called the Number of Entries and the
Maximum Cache Size. A single cache entry represents a single URI.
Tuning
You can set the maximum number of cached entries in the Admin Console in the Maximum
Entries field on the configuration's Performance tab
⇒
Cache tab, under File Cache. In the
command-line interface, use
wadm set-file-cache-prop
and set the
max-entries
property.
The default is 1024. The range of values is 1-1048576.
File Cache Hit Ratio (Cache Hits / Cache Lookups)
The hit ratio available through
perfdump
gives you the number of file cache hits compared to
cache lookups. Numbers approaching 100% indicate that the file cache is operating effectively,
while numbers approaching 0% could indicate that the file cache is not serving many requests.
To figure this number yourself using the statistics provided through the Admin Console, divide
the Total Cache Hits by the sum of the Total Cache Hits and the Total Cache Misses.
This setting is not tunable.
Maximum Age
This field 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.
Using Monitoring Data to Tune Your Server
Sun Java System Web Server 7.0 Update 1 Performance Tuning, Sizing, and Scaling Guide • 62