Setting up WebLogic Clusters 10-25
4. If you have not already done so, click Lock Edit in the top left corner of the
Console.
5. Select Configuration Tuning.
6.
Select the Enable Native IO check box.
7. Click Save.
8. Click Activate Changes in the top left corner of the Console to activate your
changes.
10.2.18.1.2 Set the Number of Reader Threads on Machines that Host Server Instances By
default, a WebLogic Server instance creates three socket reader threads upon booting. If you determine that your cluster system may utilize more than three sockets during
peak periods, increase the number of socket reader threads:
1.
Open the WebLogic Server Administration Console.
2. Select Environments Servers.
3.
Select the name of the server instance you want to configure.
4. If you have not already done so, click Lock Edit in the top left corner of the
Console.
5. Select Configuration Tuning.
6.
Edit the percentage of Java reader threads in the Socket Readers field. The number of Java socket readers is computed as a percentage of the number of total
execute threads as shown in the Execute Threads field.
7. Click Save to save your changes.
8. Click Activate Changes in the top left corner of the Console to activate your
changes.
10.2.18.1.3 Set the Number of Reader Threads on Client Machines On client machines, you
can configure the number socket reader threads in the Java Virtual Machine JVM that runs the client. Specify the socket readers by defining the
-Dweblogic.ThreadPoolSize=value and -Dweblogic.ThreadPoolPercentSocketReaders=value options in the Java
command line for the client.
10.2.18.2 Configure Multicast Time-To-Live TTL
If your cluster spans multiple subnets in a WAN, the value of the Multicast Time-To-Live TTL parameter for the cluster must be high enough to ensure that
routers do not discard multicast packets before they reach their final destination. The Multicast TTL parameter sets the number of network hops a multicast message makes
before the packet can be discarded. Configuring the Multicast TTL parameter appropriately reduces the risk of losing the multicast messages that are transmitted
among server instances in the cluster.
For more information about planning your network topology to ensure that multicast messages are reliably transmitted see
Section 3.1.1.1.1, If Your Cluster Spans Multiple Subnets In a WAN.
To configure the Multicast TTL for a cluster, change the Multicast TTL value on the Multicast page for the cluster in the Administration Console. The config.xml
excerpt below shows a cluster with a Multicast TTL value of three. This value ensures that the clusters multicast messages can pass through three routers before being
discarded:
10-26 Using Clusters for Oracle WebLogic Server
Cluster Name=testcluster
ClusterAddress=wanclust MulticastAddress=wanclust-multi
MulticastTTL=3
10.2.18.3 Configure Multicast Buffer Size
If multicast storms occur because server instances in a cluster are not processing incoming messages on a timely basis, you can increase the size of multicast buffers.
For information on multicast storms, see Section 3.1.1.1.4, If Multicast Storms Occur.
TCPIP kernel parameters can be configured with the UNIX ndd utility. The udp_ max_buf parameter controls the size of send and receive buffers in bytes for a UDP
socket. The appropriate value for udp_max_buf varies from deployment to deployment. If you are experiencing multicast storms, increase the value of udp_max_
buf by 32K, and evaluate the effect of this change.
Do not change udp_max_buf unless necessary. Before changing udp_max_buf, read the Sun warning in the UDP Parameters with Additional Cautions section in the
Internet Protocol Suite Tunable Parameters chapter in Solaris Tunable Parameters Reference Manual at
http:download.oracle.comdocscdE19253-01817-0404chapter4-7 0index.html
.
10.2.18.4 Configure Multicast Data Encryption
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