Database services support WebSphere® Business Monitor through
two data movement services: State to Runtime and Runtime to Historical. These
data movement services are completely independent of each other. Each data
movement service supports one or more business
measures models.
For each business measures model supported
by a data movement service, a set of Capture and Apply servers is created.
In the current architecture, there is, by default, one Capture server and
one Apply server for each business measures model.
You can have more than one Capture or Apply server by changing parameters in
the following parameter groups: Capture Policy Parameters, Apply Policy Parameters,
and Apply Group Policy Parameters.
If the business
measures models are very
large, having one Capture and Apply server per model per data movement service
may affect the performance and
is a good candidate to benefit from modifying these parameters to improve
performance. With adequate hardware and table space and buffer pool planning,
it may be possible to improve performance by adding additional capture and
apply servers.
Additional capture servers can increase the rate at which data is captured
for the tables of a business measures model.
You can decrease either or both Capture Policy Parameters. Each additional
capture server will take, in return, additional database space to store its
control information as well as additional processor and I/O time. However,
increasing the number of servers can make information available more quickly
for the Apply components and may improve the throughput of the overall system.
Additional apply servers also add another benefit. In the current architecture,
apply servers operate on their assigned tables serially. The larger the number
of business measures groups and tables assigned to a single apply server,
the longer it takes to process all of the entries. Adding additional apply
servers can improve performance by processing these business measures groups
in parallel. This requires adequate hardware and a good table space and buffer
pool plan to avoid I/O contention.
It is not recommended to change the defaults of the Apply Group Policy
Parameters.
How to Specify Policy Parameters:
Locate the machine hosting the Monitor Server and find the Monitor installation
directory. For example: 'C:\IBM\WebSphere\Monitor' on Windows. Under this
subdirectory there should be a directory named 'rm' and under that directory
there should be another directory named 'config'. In this example, 'C:\IBM\WebSphere\Monitor\rm\config'
would be the full path of the directory.
Create a new file called 'DS_Replication_Policy_Defaults.properties' in
the config directory. If this file exists, then the Data Services components
will read this file for user specified overrides of Performance Policy parameters.
Parameters are specified as follows:
- A default value for all Data Movement Services: POLICY_NAME=<POLICY_VALUE>
- A specific value for a particular Data Movement Service: <SERVICE_NAME>.POLICY_NAME=<POLICY_VALUE>
- Currently the only valid service names are: State_to_Runtime and Runtime_to_Historical.
During Data Movement Service processing, the system looks for service specific
values first, followed by explicit default values, followed by internal or
implicit default values.
Capture policy parameters
Capture policy parameters change the way that business measures groups
are assigned to Capture servers. There is always one Capture server for every
business measures model, but unlike the previous architecture,
it is now possible to assign multiple business measures groups to the same
Capture server, rather than having a separate server for each.
- POLICY_CAPTURE_MAX_GROUPS_PER_SERVER
- This policy essentially controls how many groups can be allocated to a
particular Capture server that is assigned to the parent business measures model.
During the assignment phase, if the system could not find an existing Capture
server that can accommodate an additional business measures group and still
comply with this policy, then a new Capture server is created to service the
new business measures group.
Note: During change management, these servers
will not be rebalanced. To rebalance, you will have to undeploy all of the
replication artifacts supporting this business measures model and
then regenerate them as a new model. This policy will not prevent the assignment
of a business measures group to a new Capture server. Also this policy will
not affect assignment of a business measures group during change management
if that business measures group is already assigned to a Capture server.
- The default value is currently 50.
- Valid values are shown in the following table.
POLICY_CAPTURE_MAX_GROUPS_PER_SERVER
values
Value |
Description |
-1 |
Policy is disabled. |
0 |
Has the same effect as 1; will always create a new Capture
server for each business measures group. |
> 1 |
Applies policy based on this number. |
- POLICY_CAPTURE_MAX_TABLES_PER_SERVER
- This policy controls how many tables can be assigned to a particular server
regardless of the number of groups. If a business measures group has 10 tables
associated with it, and an existing Capture server has 10 tables and the policy
is set to 19, then by policy, a new Capture server will be created to service
this new business measures group.
Note: Even if a business measures group by
itself exceeds this policy, the policy will not prevent its assignment to
a new Capture server. Also this policy will not affect assignment of a business
measures group during change management if that business measures group is
already assigned to a Capture server.
- The default value is currently -1.
- Valid values are shown in the following table.
POLICY_CAPTURE_MAX_TABLES_PER_SERVER
values
Value |
Description |
< 0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Capture server for
each new business measures group. |
> 1 |
Applies policy based on this number. |
- POLICY_CAPTURE_MIN_PERCENT_FREE_AFTER_GROUP_ADD
- This policy controls how many tables must be free (as compared to POLICY_CAPTURE_MAX_TABLES_PER_SERVER)
after a business measures model is assigned
to a Capture server.
Note: Even if a business measures group by itself exceeds
this policy, the policy will not prevent its assignment to a new Capture server.
Also this policy will not affect assignment of a business measures group
during change management if that business measures group is already assigned
to a Capture server.
- The default value is currently -1.
- Valid values are shown in the following table.
POLICY_CAPTURE_MIN_PERCENT_FREE_AFTER_GROUP_ADD
values
Value |
Description |
< 0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Capture server for
each new business measures group. |
>1 and < 100 |
Policy will be applied based on this threshold. |
>=100 |
Same as 1; will always create a new Capture server for
each new business measures group. |
Apply policy parameters
Apply policy parameters change the way that business measures groups are
assigned to Apply servers. At present, there is always one Apply server for
every business measures model, but unlike the previous architecture, it is
now possible to assign multiple business measures groups to the same Apply
server, rather than having a separate server for each.
- POLICY_APPLY_IS_CONSISTENT_WITH_CAPTURE
- POLICY_APPLY_MAX_GROUPS_PER_SERVER
- This policy controls how many groups can be allocated to a particular
Apply server that is assigned to the parent business measures model.
If, during the assignment phase, no Apply servers have reached threshold,
then a new Apply server will be created to service the new business measures
group.
Note: During change management, these servers will not be rebalanced.
To rebalance, you will have to undeploy all of the replication artifacts supporting
this business measures model and then regenerate
them as a new model. This policy will not prevent the assignment of a business
measures group to a new Apply server. Also this policy will not affect assignment
of a business measures group during change management if that business measures
group is already assigned to an Apply server.
- Default Value =50.
- Valid Values are shown in the following table.
POLICY_APPLY_MAX_GROUPS_PER_SERVER
values
Value |
Description |
< 0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Apply server for
each new business measures group. |
>1 |
Applies policy based on this number. |
- POLICY_APPLY_MAX_APPLYGROUPS_PER_SERVER
- This policy controls the allocation of Apply groups to a particular server.
This policy would typically be used in conjunction with the Apply group policies
to control the distribution of business measures to a server. Apply groups
in DB2® are
called subscription sets.
Note: During change management, these servers will
not be rebalanced. To rebalance, you will have to undeploy all of the replication
artifacts supporting this business measures model and
then regenerate them as a new model. This policy will not prevent the assignment
of a business measures group to a new Apply server. Also this policy will
not affect assignment of a business measures group during change management
if that business measures group is already assigned to an Apply server.
- Default Value =-1.
- Valid values are shown in the following table.
POLICY_APPLY_MAX_APPLYGROUPS_PER_SERVER
values
Value |
Description |
<0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Apply server for
each new business measures group. |
>1 |
Applies policy based on this number. |
- POLICY_APPLY_MAX_TABLES_PER_SERVER
- This policy controls the allocation of business measure groups based on
the number of tables allowed per server.
Note: During change management, these
servers will not be rebalanced. To rebalance, you will have to undeploy all
of the replication artifacts supporting this business measures model and
then regenerate them as a new model. This policy will not prevent the assignment
of a business measures group to a new Apply server. Also this policy will
not affect assignment of a business measures group during change management
if that business measures group is already assigned to an Apply server.
- Default Value =-1.
- Valid values are shown in the following table.
POLICY_APPLY_MAX_TABLES_PER_SERVER
values
Value |
Description |
<0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Apply server for
each new business measures group. |
>1 |
Applies policy based on this number. |
Apply Group policy parameters
These policies affect how business measures groups are allocated to Apply
groups; in DB2 these
are subscription sets. Refer to DB2 Replication documentation regarding
the best way to allocate tables across subscription sets. Replication
Manager always chooses to allocate one business measure group per subscription
set.
- POLICY_APPLY_MAX_TABLES_PER_APPLYGROUP
- This policy controls the allocation of business measure groups based on
the number of tables allowed per Apply group.
- Default Value =-1
- Valid values are shown in the following table.
POLICY_APPLY_MAX_TABLES_PER_APPLYGROUP
values
Value |
Description |
<0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Apply group for
each new business measures group. |
>1 |
Applies policy based on this number. |
- POLICY_APPLY_MAX_GROUPS_PER_APPLYGROUP
- This policy controls the allocation of business measure groups based on
the number of business measure groups per Apply group.
- Default Value =1
- Valid Values are shown in the following table.
POLICY_APPLY_MAX_GROUPS_PER_APPLYGROUP
values
Value |
Description |
<0 |
Policy is disabled. |
-1 |
Policy is disabled. |
0 |
Same as 1; will always create a new Apply group for
each new business measures group. |
>1 |
Applies policy based on this number. |