Before Release of Oracle Clusterware 11g release 2, we define a specific instance belong to specific node.a DBA manages each instance of the database by defining specific instances to run on specific nodes in the cluster. And it is pretty well with small no of nodes in your RAC database.
But when no of nodes increase in your clusterware , adding and removing nodes become painful. So then there is a Serverpool introduced, where resources that Oracle Clusterware manages are contained in logical groups of servers called server pools. Resources are hosted on a shared infrastructure and are contained within server pools.
Prior of Oracle 11g R.2 RAC there was Database Administrator based management available because adding node to Clusterware, adding and removing instance from Oracle RAC, creating redo logs, control files, undo tablespace for specific new instance were done by Database Administrator. But after Oracle 11g R.2 RAC these all tasks are automated using server pool – a new feature of Oracle 11g RAC.
To read more about admin managed database Basic on Administrator Managed and Policy Managed Database in Oracle Rac
There are 2 types of server pools available in Oracle 11g R.2 clusterware.
- Free Pool: If it’s going to be a fresh installation of the clusterware environment, all the nodes would be attached to this pool first of all. From this pool only, the nodes would move to the manually created server pools. As like the Generic pool, this is also an internally managed pool but still some attributes are available to be modified by the dba like IMPORTANCE.
- Generic Pool : When you upgrade your existing version of the clusterware to 11.2, all the nodes get mapped to the in-built Generic pool. This is an internally managed server pool and the modification of the attributes of this pool is not allowed. Besides the addition of the nodes of the previous cluster, in 11.2, when you create a database which is Admin-managed, that also becomes a part of the Generic Pool as a child pool of it.
We can configure Server Pool with three main parameters for Minimum no of Servers, Maximum no of Servers and Importance of that Server Pool.
Configuration of Server Pool in Oracle RAC :
- Check Status of serverpool using following command :
[oracle@rac2 ~]$ srvctl status srvpool Server pool name: Free Active servers count: 0 Server pool name: Generic Active servers count: 1 Server pool name: mypool Active servers count: 1 [oracle@rac2 ~]$
- To add serverpool use following command :
To view all options supported with srvctl add srvpool command use -h
[oracle@rac1 ~]$ srvctl add srvpool -h
Adds a server pool to the Oracle Clusterware.
Usage: srvctl add srvpool -g <pool_name> [-l <min>] [-u <max>] [-i <importance>] [-n "<server_list>"] [-f]
-g <pool_name> Server pool name
-l <min> Minimum size of the server pool (Default value is 0)
-u <max> Maximum size of the server pool (Default value is -1 for unlimited maximum size)
-i <importance> Importance of the server pool (Default value is 0)
-n "<server_list>" Comma separated list of candidate server names
-f Force the operation even though some resource(s) will be stopped
-h Print usage
To add serverpool
[oracle@rac1 ~]$ srvctl add srvpool -g mysrvpool -l 1 -u 1 -i 99
Stay tuned for More articles on Oracle RAC
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