You can use the coregroupsplit.py script to split your
existing cell into multiple core groups. Consider running this script
if you have more than 40 WebSphere® Application
Server related
processes such as application servers, node agents, and on demand
routers (ODRs) defined in your core group.
Purpose
The coregroupsplit.py script divides
your existing cell into multiple core groups. If a server changes
its core group membership, then you must restart the entire cell to
prevent partitions from forming. For this reason, this default script
options for script do not change the core group membership of servers
that are members of any core groups other than the DefaultCoreGroup
core group.
Running the script attempts to satisfy the following
best practices for core groups:
- Each core group must have fewer than 40 servers. This best practice
is possible only when you have an adequate ratio of nodes to servers
in your cell.
- Each core group must be equipped with at least three core group
bridges. This best practice is possible only when you have an adequate
ratio of nodes to servers in your cell.
- Each cluster must remain fully mapped to a single core group.
- If you use the -createbridges parameter,
the core group bridges and coordinators are preferably hosted on otherwise
idle nodes.
This script also tunes the high availability manager for optimum
performance. By default, the script configures a core group bridge
on each node agent in the cell. The script increases the number of
core groups until it reaches the optimal level, depending on the number
of nodes and servers in the cell. The core group bridge node agents
are configured as a part of the DefaultAccessPointGroup access point
group in a mesh topology. In the preferred mesh topology, all of the
access points are collected into a single access point group. As a
result, all bridge interfaces can directly intercommunicate.
Remember
that you must give core group bridges at least 512 MB of Java™ virtual machine (JVM) space.
Location
The coregroupsplit.py script is in
the install_root/bin directory.
Usage
The default script usage follows:
./wsadmin.sh -lang jython -f coregroupsplit.py
Running
this script might result in unbalanced core groups, in which some
core groups are loaded more or less than other core groups. You can
rerun this script to rebalance core group membership, but in this
case you must restart the entire cell for the changes to take effect.
To rerun the script, use the following command:
./wsadmin.sh -lang jython -f coregroupsplit.py -reconfig
Parameters
- -reconfig
- Performs a full reconfiguration to rebalance the distribution
of servers among the core groups.
- -linked
- Creates a ring topology of core group bridges.
- -createbridges
- Creates separate core group bridge processes instead of creating
the bridge in the node agent.
- -numcoregroups
- Specifies the number of core groups to create.
- -datastacksize
- Specifies a number of megabytes that overrides the default data
stack size.
- -proxycoregroup
- Places the on demand routers (ODR) and proxy servers in a separate
core group.
- -odrcoregroup
- Places the on demand routers (ODR) and proxy servers in a separate
core group.
- -nosave
- Does not save any changes made to the core group. You can use
this option to test setting parameters and running the script.
- -debug
- Prints troubleshooting information.
- -nodesPerCG:number
- Specifies the number of node agents that are required for each
core group.
- -numberOfServersPerCG:number
- Specifies the maximum number of servers for each core group.
- -bridgeHeapSize:number
- Specifies the server heap size of the core group bridge in megabytes.
Examples
The following example results in a
linked topology where the core group bridges are connected in a ring:
./wsadmin.sh -lang jython coregroupsplit.py -linked
You
can also use this script to create static cluster that are dedicated
as core group bridges for communication within the core group. Use
the following example:
./wsadmin.sh -lang jython coregroupsplit.py -createbridges