Sun Microsystems Sun Java System Web Server 7.0, Manual

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Tuning
You can set the maximum size of the DNS cache in the Admin Console in the Maximum Cache
Size field on the configuration's Performance tab
⇒
DNS sub tab, under DNS Cache Settings.
To set it using the command-line-interface, use
wadm set-dns-cache-prop
and set the
max-entries
property. The default cache size is 1024. The value range is 2-32768.
Hit Ratio (Cache Hits / Cache Lookups)
The hit ratio in
perfdump
displays the number of cache hits compared to the number of cache
lookups. You can compute this number using the statistics in the Admin Console by dividing
the Total Cache Hits by the sum of the Total Cache Hits and the Total Cache Misses.
This setting is not tunable.
Async DNS Enabled/Disabled
Async DNS enabled/disabled displays whether the server uses its own asynchronous DNS
resolver instead of the operating system's synchronous resolver. By default, Async DNS is
disabled. If it is disabled, this section does not appear in
perfdump
. To enable it using the Admin
Console, on the configuration's Performance tab
⇒
DNS tab, under DNS Lookup Settings,
select Asynchronous DNS. To enable it using the command-line interface, use
wadm
set-dns-prop
and set the
async
property to true.
Java Virtual Machine (JVM) Information
JVM statistics are displayed through the Admin Console, the CLI, and
stats-xml
only. They
are not shown in
perfdump
.
The following table shows an example of the JVM statistics displayed in the Admin Console:
TABLE 2–7
Java Virtual Machine (JVM) Statistics
Virtual Machine Name Java HotSpot
TM
Server VM
Virtual Machine Vendor Sun Microsystems Inc.
Virtual Machine Version 1.5.0_06-b05
Heap Memory Size 5884856
Elapsed Garbage Collection Time (milli seconds) 51
Present Number of Classes Loaded 1795
Total Number of Classes Loaded 1795
Using Monitoring Data to Tune Your Server
Sun Java System Web Server 7.0 Update 1 Performance Tuning, Sizing, and Scaling Guide • 70