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Core group custom properties

Use these custom properties for advanced configurations for core groups.

This topic references one or more of the application server log files. As a recommended alternative, we can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files on distributed and IBM i systems. We can also use HPEL in conjunction with the native z/OS logging facilities. If we are using HPEL, we can access all of the log and trace information using the LogViewer command-line tool from the server profile bin directory. See the information about using HPEL to troubleshoot applications for more information on using HPEL.

To configure a custom property, on the indicated Custom properties page, complete one of the following actions:

Best practice: When set the core group custom properties, verify the core group or the cell is in a stable state. You do not want to set these custom properties when we are simultaneously starting or stopping servers. Also, ensure that the high availability manager is in a known, good state. With these best practices in mind, consider the following best practices for some specific core group custom properties:

bprac

We can use the custom properties page to define the following core group custom properties:


IBM_CS_DATASTACK_MEG

Eliminate a condition that is reported by a message that is displayed repeatedly in the SystemOut.log file.

This topic references one or more of the application server log files. As a recommended alternative, we can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files on distributed and IBM i systems. We can also use HPEL in conjunction with the native z/OS logging facilities. If we are using HPEL, we can access all of the log and trace information using the LogViewer command-line tool from the server profile bin directory. See the information about using HPEL to troubleshoot applications for more information on using HPEL.

Deprecated feature: This custom property is deprecated. Do not use this custom property unless you are running in a mixed cell environment that includes at least one core groups containing a mixture of Version 7.0 and Version 6.x processes.depfeat

Mixed-version environment: If we are running in a mixed cell environment, and we have core groups containing a mixture of Version 7.0 and Version 6.x processes, you must continue to use the IBM_CS_DATASTACK_MEG core group custom property to change how frequently the Discovery Protocol attempts to open a new network.

We might see a message, similar to the following message, repeated multiple times in the SystemOut.log file:

If the member IP address is in the format of a dotted decimal IP address and port, we can eliminate these messages by increasing the amount of memory that is allocated to the core stack used for core group communication. Increase the value of this property until you no longer see the message in the SystemOut.log file. Because the memory is dynamically allocated, setting a larger stack size than we need does not cause memory problems.

We can also set this custom property:

See Core group bridge custom properties for more information about how to set the property at those levels.

Units Megabytes
Default 5

To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


IBM_CS_FD_CONSECUTIVE_MISSED

This custom property is used to specify the consecutive number of heartbeats that must be missed before the core group member is considered failed.

Deprecated feature: This custom property is deprecated. Do not use this custom property unless you are running in a mixed cell environment that includes at least one core groups containing a mixture of Version 7.0 and Version 6.x processes.depfeat

However, we can also use the Discovery and failure detection page in the console to change the settings for the Discovery and Failure Detection protocols. Unless you are running in a mixed cell environment, using the console is the preferred technique for changing the settings for the Discovery and Failure Detection protocols because the IBM_CS_FD_CONSECUTIVE_MISSED property is deprecated.

Mixed-version environment: If we are running in a mixed cell environment, and we have core groups containing a mixture of Version 7.0 and Version 6.x processes, you must continue to use the IBM_CS_FD_CONSECUTIVE_MISSED core group custom property to change how many consecutive heartbeats a core group member must miss before that core group member is considered failed..

Units Seconds
Default 6

To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


IBM_CS_FD_PERIOD_SECS

This custom property is used to change how frequently the Failure Detection Protocol checks the core group network connections that the discovery protocol establishes. The Failure Detection Protocol notifies the Discovery Protocol if a connection failure occurs.

Deprecated feature: This custom property is deprecated. Do not use this custom property unless you are running in a mixed cell environment that includes at least one core groups containing a mixture of Version 7.0 and Version 6.x processes.depfeat

However, we can also use the Discovery and failure detection page in the console to change how frequently the high availability manager Discovery Protocol checks for new core group members. Unless you are running in a mixed cell environment, using the console is the preferred technique for updating this setting because the IBM_CS_FD_PERIOD_SECS property is deprecated.

Mixed-version environment: If we are running in a mixed cell environment, and we have core groups containing a mixture of Version 7.0 and Version 6.x processes, you must continue to use the IBM_CS_FD_PERIOD_SECS core group custom property to change how frequently the Failure Detection Protocol checks the core group network connections that the discovery protocol establishes..

Units Seconds
Default 6

To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


IBM_CS_HAM_PROTOCOL_VERSION

Use this custom property to configure all of the members of the selected core group to run with a different version of the higher level core group protocol, which is also referred to as the high availability manager protocol. We can change the value of this property while the core group members continue to run. After you save and synchronize the changed value to all of the nodes containing core group processes, the high availability manager automatically detects the configuration change and starts using the new core group protocol version to communicate with the core group members.

Version ID Required Minimum Product Level Description
6.0.2.31 6.0.2.31 for Version 6.0, 6.1.0.19 for Version 6.1, 7.0.0.1 for Version 7.0 This protocol version is the original or base version of the HAM protocol. This version was included in the 6.0.2.31, 6.1.0.19, and 7.0.0.1 service packs to facilitate core group bridge scalability. This version is recommended for topologies containing multiple core groups and core group bridges as part of their configuration.

Set this custom property to the value in the Version ID column of the previous table. To set this custom property, complete the following process:

  1. Stop the core group bridges.

  2. Set the custom property on all core groups.

  3. Restart the high availability coordinators in all core groups.

  4. Start the core group bridges.


IBM_CS_IP_REFRESH_MINUTES

Use this custom property to adjust how frequently the core group IP cache is cleared.

The caching of name-to-IP address information at the core group level eliminates some of the system overhead required to assign IP addresses to core group members.

following table describes the units, default, and acceptable values
Units Minutes
Default 1
Acceptable values Any positive integer. 1 is the minimum value that can be specified

To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


IBM_CS_OOM_ACTION

Explicitly enable exception handlers that are specific for OutOfMemoryExceptions that occur when sending or receiving network messages. When this property is set to Isolate, if an OutOfMemoryException occurs when a network message is being sent or received, these exception handlers stop High Availability Manager communications to the Out of Memory process.

If IBM_CS_OOM_ACTION=Isolate is not added to the configuration settings for a core group, if a core group process runs out of memory, the Out of memory process might not be able to respond to all messages. This situation prevents multi-step protocols from completing, and prevents the starting server from receiving its initial view of the distributed state.


IBM_CS_SOCKET_BUFFER_SIZE

Use this custom property to change the size of the socket buffer that the core group transport obtains.

  • Configure core group socket buffers includes a table that shows the relationship between the values that can be specified for this property and the underlying memory allocation size per socket buffer type.

    Information Value
    Units One of the following:

    • No over rides

    • small

    • medium

    • large

    Default 2 megabytes for all buffer types.

    To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


    IBM_CS_UNICAST_DISCOVERY_INTERVAL_SECS

    This custom property is used to change how frequently the high availability manager Discovery Protocol checks for new core group members. A new core group member is not able to communicate with other core group members until the Discovery Protocol establishes communication between the new member and the existing members.

    Deprecated feature: This custom property is deprecated. Do not use this custom property unless you are running in a mixed cell environment that includes at least one core groups containing a mixture of Version 7.0 and Version 6.x processes.depfeat

    However, we can also use the Discovery and failure detection page in the console to change how frequently the high availability manager Discovery Protocol checks for new core group members. Unless you are running in a mixed cell environment, using the console is the preferred technique for updating this setting because the IBM_CS_UNICAST_DISCOVERY_INTERVAL_SECS property is deprecated.

    Mixed-version environment: If we are running in a mixed cell environment, and we have core groups containing a mixture of Version 7.0 and Version 6.x processes, you must continue to use the IBM_CS_UNICAST_DISCOVERY_INTERVAL_SECS core group custom property to change how frequently the Discovery Protocol attempts to open a new network.

    Units Seconds
    Default 30

    To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


    IBM_CS_WIRE_FORMAT_VERSION

    Use this custom property to configure all of the members of the selected core group to run with a different version of the core group protocol. We can change the value of this property while the core group members continue to run. After you save and synchronize the changed value to all of the nodes containing core group processes, the high availability manager automatically detects the configuration change and starts using the new core group protocol version to communicate with the core group members.

    Deprecated feature: Protocol versions 6.0.0 and 6.0.2.9 are deprecated. Whenever possible you should use a newer protocol version.depfeat

    Version ID Required Minimum Product Level Description
    6.0.0 6.0.0.0 for Version 6.0, 6.1.0.0 for Version 6.1, 7.0.0.0 for Version 7.0 This protocol version is the original or base version. All versions of the high availability manager can use this protocol version. If we do not specify a particular protocol version the high availability manager uses this version.
    6.0.2.9 6.0.2.9 for Version 6.0.2, 6.1.0.0 for Version 6.1, 7.0.0.0 for Version 7.0. This protocol version was included in the 6.0.2.9 service pack, and in Versions 6.1, and 7.0 of the product to facilitate core group bridge scalability. This version is recommended for large topologies containing multiple core groups and core group bridges as part of their configuration.
    6.1.0 6.1.0.0 for Version 6.1, 7.0.0.0 for Version 7.0 This protocol version was included in Versions 6.1, and 7.0 of the product to add core group scalability improvements, and more support for large topologies.

    We can set this custom property to the values listed in the Version ID column of the previous table. Set the value to the most current value that is possible for the environment.

    To set a value for this custom property, in the console, click Servers > Core Groups > Core group settings > core_group_name. Then, under Additional Properties, click Custom properties.


    Related concepts

  • Core group discovery and failure detection protocols


    Related tasks

  • Use High Performance Extensible Logging to troubleshoot applications