Set core group socket buffers

Overview

Operating systems send and receive data over sockets. We can set the amount of memory allocated per socket used as data buffers.

For AIX review TCP sockets values for...

• tcp_sendspace
• tcp_recvspace
• sb_max settings

For Linux, review...

• tcp_rmem
• tcp_wmem

Use WAS PMI to determine the average message size that the core group transport handles. If the OS setting for the default buffer size is smaller than the average message size, make one of the following changes:

• Change the default buffer size setting for the operating system.

  This action might be inappropriate because it might affect the operation of other applications running on this operating system.

• Set the size of the socket buffer that the core group transport obtains, using the core group custom property...

  IBM_CS_SOCKET_BUFFER_SIZE

Relationship between the values specified and the underlying memory allocation size per socket buffer type...

Socket Buffer Type	Value 0 buffer size	Value 1 buffer size	Value 2 buffer size	Value 3 buffer size
Unicast receive	OS default	64 KB	256 KB	1 MB
Unicast send	OS default	OS default	64 KB	128 KB
Multicast receive	OS default	512 KB	1 MB	3 MB

We might want to change the size of the core group buffers in the following circumstances:

• Per IBM Support
• As part of installing another WebSphere product.
• To change the behavior of the core group transport without affecting the behavior of other sockets.
• To tune the network communication path of the system to the application.

 

Change the socket buffer space the core group transport allocates

To change the socket buffer space the core group transport allocates, go to...

Servers | Core Groups | Core group settings | core_group_name | Additional Properties | Custom properties

...and set...

IBM_CS_SOCKET_BUFFER_SIZE

Specify either 0, 1, 2, or 3.

Click OK and then click Review.

Synchronize changes with nodes, click Save, and restart all members of the core group.

 

Related

Core groups (high availability domains)
Set up a high availability environment