Differences between Admin-Managed and Policy-Managed for Oracle 11gR2 RAC instances

When creating an instance in Oracle 11gR2 RAC, the following configuration types are selected: Admin-Managed and Policy-Managed:

The official website documents are explained as follows:

6.1 Understanding ServerPools

Server pools arelogical divisions of a cluster into pools of servers, which are allocated tohost databases or other applications. Server pools are managed using crsctl andsrvctl commands.

Each server poolname must be unique within the cluster. You cannot have two server pools usingthe same name.

There are twostyles of server pool management:

(1)Administrator-managed:

Databaseadministrators define on which servers a database resource shocould run, andplace resources manually as needed. This is the management strategy used inprevious releases.

(2)Policy managed:

Databaseadministrators specify in which server pool (excluding generic or free) thedatabase resource will run. Oracle Clusterware is responsible for placing thedatabase resource on a server.

From: http://download.oracle.com/docs/cd/E11882_01/install.112/e10813/srvpool.htm#BHBBGEIE

The configuration type andOracle 11gR2 RACRelated to new features: Server pool(Server Pools)

The server Pool provides a new method to shape resources in a cluster. It allows you to divide a cluster into multiple logical units, which is useful in a shared environment. All nodes in the cluster of version 11.2, whether explicit or implicit, are part of the server pool. By default, two pools are generated after a new installation: free pool and generic pool. The general pool is used for backward compatibility, it stores databases earlier than version 11.2 or administrator-managed databases in version 11.2. All unspecified nodes are allocated to the free pool.

The server pool is exclusive to each other and contains some attributes, such as the maximum and minimum number of nodes, importance, and name. The importance attribute of the server pool is used to ensure that low-priority workloads do not beat high-priority workloads to obtain resources. It is possible to re-allocate servers from one pool to another, which will be interesting in capacity management. The cluster software can automatically learn the minimum size requirement of the server pool from the mobile servers in other server pools.

The server pool is accompanied by a new method for busy RAC databases. Before Oracle 11.2, the Administrator is responsible for adding or deleting instances from the RAC database, including creating and enabling public online redo log threads and undo tablespace.

The server pool (and OMF used in ASM) automates these operations through policy-managed databases.

Databases managed by administrators(Administrator-managed)That is, as mentioned in the name, all must be managed by the database administrator. In other wordsIn Oracle 11.1PreviousRACDatabase.

Database managed by policy(Policy-manageddatabase)Use automation features to add and delete instances and services.The number of nodes started by the database managed by the policy is configured by the base of the server pool. In other words, if you need a new instance, you only need to allocate a new node to the server pool of the database, and Oracle will perform the rest of the work.

In combination with the server pool, Grid Infrastructure introduces another feature called Role SeparatedManagement ). In a shared environment, administrators are restricted when managing their respective server pools. The Access Control Lists is used to allocate Access to resources. A new role named cluster administrator is introduced here ).

By default, Grid Infrastructure software owner "grid" and root users are fixed cluster administrators. You can add new system users as cluster administrators. each user has several resources, types, and permissions on the server pool. Separation of duties can now be implemented at the cluster level. Note that the permissions of grid and root users are high.