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Background documentation Cluster Manager  Locate the document in its SAP Library structure

The Cluster Manager provides a set of properties for communication between the elements in the cluster. It integrates new elements and notifies the modules installed on each element when an element is removed. This manager runs on both servers and dispatchers.

Dispatcher

Property

Description

Default Value

barrier.dependent

Determines if the startup and shutdown barriers are dependent. If the property value is "true", there can be only one starting or stopping element in the box/cluster at the moment. If it is "false", there can be only one starting and one stopping element.

false

barrier.shutdown

Determines the serialization kind of the element's shutdown (similar to barrier.startup).

none

barrier.startup

Determines the serialization kind of the element's startup. The following values are available: "none" – no serialization; "box" – serialization in the boundaries of the box, that is, the nodes in one box will be started one by one; "cluster" – serialization in the boundaries of the whole cluster.

none

barrier.timeout

An integer that specifies a timeout in milliseconds. Within this timeout, the element is forced to recheck if it can pass the barrier.

Recommendation

The system uses this property for optimization purposes only. We do not recommend that you change it.

 

10000

element.clusterId

The identification number of the cluster element. The ID is unique for the cluster.

Caution

Do not modify this property.

Assigned at installation time

element.groupId

The group ID of the element.

Caution

Do not modify this property.

Assigned at installation time

element.name

Specifies the name of the cluster element.

Dispatcher <n>

element.type

Specifies the type of the cluster element (server or dispatcher).

Caution

Do not modify this property.

dispatcher

ms.backup.message.number

The length of the internal message backup queue.

Caution

Do not modify this property.

10

ms.confirmation.timeout

The timeout period (in milliseconds) that a joining cluster node waits for the confirmation replies from the cluster participants.

30000

ms.eyecatcher.control

Specifies if the eyecatcher control is activated.

Caution

Do not modify this property.

false

ms.host

This is the host (IP address), where the Message Server is running.

Depends on the settings made at installation

ms.keepalive

If there has been no communication between a cluster node and the message server for the specified timeout period, the node triggers a liveliness check (ping/pong protocol). The value is in milliseconds.

20000

ms.message.pool.size

Defines the size of the message library pool. The size of this pool can be changed for optimization purposes.

10000

ms.notification.timeout

Defines the timeout (in milliseconds) for receiving an acknowledgement by the message server that the message has been delivered.

Caution

Do not modify this property.

180000

ms.port

The port on which the Message Server listens for connections.

3601

ms.reconnect.timeout

Specifies the timeout (in milliseconds) after which the node is no longer able to reconnect to the message server.

180000

session.buffer.size

The size of the I/O stream buffers that wrap the session socket I/O stream.

2048

session.message.queue.size

Defines the size of the session layer queue. The size of this queue can be changed for optimization purposes.

256

socket.SO_KEEPALIVE

Enables and disables the socket “keep alive” option. This property has a Boolean value. If it is false, the socket “keep alive” option is disabled.

false

socket.SO_LINGER

Enables and disables a socket linger with the specified time in seconds. The maximum timeout value is platform specific.

“-1” implies that the option is disabled. The setting only affects the socket close.

-1

socket.SO_RCVBUF

Sets the received buffer size for this socket.

This graphic is explained in the accompanying text

This property has the same use as the socket.SO_SNDBUF property described above.

65536

socket.SO_SNDBUF

Sets the send buffer size for this socket. This option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.

Increasing the buffer size can increase the performance of network I/O for high-volume connection, while decreasing it can help reduce the backlog of incoming data.

65536

socket.SO_TIMEOUT

Enables and disables the socket timeout with the specified value in milliseconds. The timeout must be > 0. A timeout of zero is interpreted as an infinite timeout, that is, the timeout is disabled.

0

socket.TCP_NODELAY

This property takes a Boolean value that specifies whether Nagle’s algorithm is disabled or enabled for this socket. Setting socket.TCP_NODELAY to “true” improves system performance, especially if multiple small portions of data are sent through the socket.

true

 

Server

Property

Description

Default Value

barrier.dependent

See above.

false

barrier.shutdown

See above.

none

barrier.startup

See above.

none

barrier.timeout

See above.

10000

element.clusterId

See above.

Assigned at installation time

element.groupId

See above.

Assigned at installation time

element.joinPort

The server listens for connections on this port.

Assigned at installation time

element.name

See above.

Server <n>

element.type

See above.

server

lazy.autoclose.timeout

Specifies the time through which the lazy connection will be open after the last large group of message is transported. After this timeout the Cluster Manager closes the connection.

The time is in milliseconds. The maximum for closing a socket is between 5 and 10 seconds.

5000

lazy.exclusive.list

A list of services for which if the Cluster Manager has to transfer messages from or to them, it always transfers them using the lazy communication mechanism without considering the lazy.threshold value.

jmx, jms_provider

lazy.message.pool.size

Specifies the size of the pool where the currently unused message objects are stored. This message objects are used by the messaging system for internal use only.

The value must be equal or greater than “0”.

10000

lazy.threshold

Specifies the size of the messages that must be sent during a time interval equal to the value set in the lazy.time.piece property so that if this size is exceeded a lazy communication is established.

The value must be equal or greater than “0”. If the value is “0”, all messages will be transferred through a lazy connection.

100000

lazy.time.piece

Specifies the time interval in milliseconds for which the quantity of messages defined by the lazy.threshold property have to be exchanged between two parties in order to open a lazy connection.

If two parties open a connection and succeed in exchanging more messages than the size defined by the lazy.threshold property for the time defined in this property, then a lazy connection will be opened.

1000

lazy.transparent.switch

If set to true, specifies that the value of the lazy.threshold property is taken into account when establishing a lazy communication. If set to false, only messages from or to the services specified in the lazy.exclusive.list property are sent through the lazy communication mechanism.

false

ms.backup.message.number

See above.

10

ms.confirmation.timeout

See above.

30000

ms.eyecatcher.control

See above.

false

ms.host

See above.

Depends on the settings made at installation

ms.keepalive

See above.

20000

ms.message.pool.size

See above.

10000

ms.notification.timeout

See above.

180000

ms.port

See above.

3604

ms.reconnect.timeout

See above.

180000

session.buffer.size

See above.

2048

session.message.queue.size

See above.

256

socket.SO_KEEPALIVE

See above.

false

socket.SO_LINGER

See above.

-1

socket.SO_RCVBUF

See above.

65536

socket.SO_SNDBUF

See above.

65536

socket.SO_TIMEOUT

See above.

0

socket.TCP_NODELAY

See above.

true

 

See also:

Cluster Manager Configuration in the Administration Manual

Communication Management in the Administration Manual

 

 

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