IBM BS029ML Self Help Guide - Page 160

Additional SUN JVM attributes, Servers, Application Servers, WebSphere_Portal, Server Infrastructure

Page 160 highlights

As the Portal Server places a greater demand on JVM memory, you should increase the Java minimum and maximum heap sizes accordingly. To view or modify the SUN JVM settings from the WebSphere Application Server Administrative Console, select Servers → Application Servers → WebSphere_Portal → Server Infrastructure → Java and Process Management → Process Definition → Java Virtual Machine. Table 5-3 shows the default and recommended values. Table 5-3 SUN JVM settings Parameter JVM initial heap size JVM maximum heap size Default value n/a n/a Recommended value 1536 2048 Additional SUN JVM attributes For the SUN JVM, we strongly recommend that you set a number of additional JVM attributes to fine-tune the behavior of the generational heap. Increase the size of the Young generation heap (NewSize and MaxNewSize), as objects in this heap should not live through more then one garbage collection (GC) cycle. Up to 50% to 60% of the total heap size can be set for the Young generation. Also, consider slightly increasing SurvivorRatio. Additionally, ensure that the Permanent generation (PermSize and MaxPermSize) is adequately sized to hold all class loaded data. This includes classes loaded at Portal Server runtime startup and dynamically compiled JSPs. If the Permanent generation becomes full, a Full GC will result. Note: The Permanent generation is not allocated from the heap defined by either the (-Xms) or (-Xmx) settings. To view or modify the SUN JVM settings from the WebSphere Application Server Administrative Console, select Servers → Application Servers → WebSphere_Portal → Server Infrastructure → Java and Process Management → Process Definition → Java Virtual Machine. Table 5-4 shows the default and recommended values. Table 5-4 Additional SUN JVM settings Parameter HotSpot Server option Default size of New Generation (in bytes) Default value n/a n/a Maximum size of New Generation (in bytes). n/a Default size of Permanent Generation n/a Maximum Permanent Generation Size n/a Ratio of Eden / Survivor Space Size n/a GC Concurrent Collector n/a GC Parallel Collector n/a Recommended value -server -XX:NewSize=(50% to 60% of heap) -XX:MaxNewSize=(50% to 60% of heap) -XX:PermSize=512m -XX:MaxPermSize=768 m -XX:SurvivorRatio=16 -XX: +UseConcMarkSweep GC -XX:+UseParNewGC 146 IBM WebSphere Portal V6 Self Help Guide

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146
IBM WebSphere Portal V6 Self Help Guide
As the Portal Server places a greater demand on JVM memory, you should increase the Java
minimum and maximum heap sizes accordingly.
To view or modify the SUN JVM settings from the WebSphere Application Server
Administrative Console, select
Servers
Application Servers
WebSphere_Portal
Server Infrastructure
Java and Process Management
Process Definition
Java
Virtual Machine
. Table 5-3 shows the default and recommended values.
Table 5-3
SUN JVM settings
Additional SUN JVM attributes
For the SUN JVM, we strongly recommend that you set a number of additional JVM attributes
to fine-tune the behavior of the generational heap. Increase the size of the Young generation
heap (NewSize and MaxNewSize), as objects in this heap should not live through more then
one garbage collection (GC) cycle. Up to 50% to 60% of the total heap size can be set for the
Young generation. Also, consider slightly increasing SurvivorRatio.
Additionally, ensure that the Permanent generation (PermSize and MaxPermSize) is
adequately sized to hold all class loaded data. This includes classes loaded at Portal Server
runtime startup and dynamically compiled JSPs. If the Permanent generation becomes full, a
Full GC will result.
To view or modify the SUN JVM settings from the WebSphere Application Server
Administrative Console, select
Servers
Application Servers
WebSphere_Portal
Server Infrastructure
Java and Process Management
Process Definition
Java
Virtual Machine
. Table 5-4 shows the default and recommended values.
Table 5-4
Additional SUN JVM settings
Parameter
Default value
Recommended value
JVM initial heap size
n/a
1536
JVM maximum heap size
n/a
2048
Note:
The Permanent generation is not allocated from the heap defined by either the
(-Xms) or (-Xmx) settings.
Parameter
Default value
Recommended value
HotSpot Server option
n/a
-server
Default size of New Generation (in bytes)
n/a
-XX:NewSize=(50% to
60% of heap)
Maximum size of New Generation (in bytes).
n/a
-XX:MaxNewSize=(50%
to 60% of heap)
Default size of Permanent Generation
n/a
-XX:PermSize=512m
Maximum Permanent Generation Size
n/a
-XX:MaxPermSize=768
m
Ratio of Eden / Survivor Space Size
n/a
-XX:SurvivorRatio=16
GC Concurrent Collector
n/a
-XX:
+UseConcMarkSweep
GC
GC Parallel Collector
n/a
-XX:+UseParNewGC