Oracle RAC Database Growth Test

Periodic monitoring of the usage of the shared cluster storage is essential to ensure that the cluster is always adequately sized to handle current and future loads. The Ora

Target of the test : Oracle Cluster

Agent deploying the test : An internal agent

Outputs of the test : One set of results for the Oracle cluster monitored.

Configurable parameters for the test

cle RAC Database Growth test monitors the usage of a shared storage, and indicates if it requires resizing.

  1. TEST PERIOD - How often should the test be executed
  2. Host – The host for which the test is to be configured
  3. Port - The port on which the server is listening
  4. orasid - The variable name of the oracle instance
  5. service name - A ServiceName exists for the entire Oracle RAC system. When clients connect to an Oracle cluster using the ServiceName, then the cluster routes the request to any available database instance in the cluster. By default, the service name is set to none. In this case, the test connects to the cluster using the orasid and pulls out the metrics from that database instance which corresponds to that orasid. If a valid service name is specified instead, then, the test will connect to the cluster using that service name, and will be able to pull out metrics from any available database instance in the cluster.

    To know the ServiceName of a cluster, execute the following query on any node in the target cluster:

    select name, value from v$parameter where name =’service_names’

  6. User – In order to monitor an Oracle database server, a special database user account has to be created in every Oracle database instance that requires monitoring. A Click here hyperlink is available in the test configuration page, using which a new oracle database user can be created. Alternatively, you can manually create the special database user. When doing so, ensure that this user is vested with the select_catalog_role and create session privileges.

    The sample script we recommend for user creation (in Oracle database server versions before 12c) for eG monitoring is:

    create user oraeg identified by oraeg

    create role oratest;

    grant create session to oratest;

    grant select_catalog_role to oratest;

    grant oratest to oraeg;

    The sample script we recommend for user creation (in Oracle database server 12c) for eG monitoring is::

    alter session set container=<Oracle_service_name>;

    create user <user_name>identified by <user_password> container=current default tablespace <name_of_default_tablespace> temporary tablespace <name_of_temporary_tablespace>;

    Grant create session to <user_name>;                                 

    Grant select_catalog_role to <user_name>;

    The name of this user has to be specified here.

  7. Password – Password of the specified database user

    This login information is required to query Oracle’s internal dynamic views, so as to fetch the current status / health of the various database components.

  8. Confirm password – Confirm the password by retyping it here.
  9. alternate view – In large environments, where the volume of transactions to the Oracle database server is generally very high, this test may take time to execute and retrieve the desired results. To ensure that the test is faster and is resource-efficient, administrators of such environments can create an alternate ‘view’ on the target Oracle database server, and grant select privileges to the view to the special database user mentioned above. Once the view is created, the test should be configured to use the alternate view for metrics collection; to achieve this, specify the name of the view in the alternate view text box. By default, this text box is set to none, which implies that the alternate view is not used by default.

    This alternate ‘view’ should be created with the following structure:

    CREATE OR REPLACE VIEW <VIEW_NAME> (
    TABLESPACE_NAME,
    FILE_ID,
    BLOCK_ID,
    BYTES,
    BLOCKS,
    RELATIVE_FNO
    ) AS
    select /*+ use_hash (tsfi, fet2) */ tsfi.tablespace_name,
           tsfi.file_id,
           fet2.block_id,
           tsfi.blocksize * fet2.blocks,
           fet2.blocks,
           tsfi.relfile#
    from   (select /*+ use_hash (ts, fi) */ ts.name tablespace_name,
                   fi.file# file_id,
                   ts.BLOCKSIZE,
                   fi.relfile#,
                   ts.ts#
            from   sys.ts$ ts,
                   sys.file$ fi
            where  ts.ts# = fi.ts#
            and    ts.online$ in (1,4)) Tsfi,
           (select f.block# block_id,
                   f.length blocks,
                   f.file# file_id,
                   f.ts#
            from   sys.fet$ f
            union all
            select f.ktfbfebno block_id,
                   f.ktfbfeblks blocks,
                   f.ktfbfefno,
                   ktfbfetsn
            from   sys.x$ktfbfe f) Fet2
    where  fet2.file_id = tsfi.relfile#
    and    fet2.ts# = tsfi.ts# ;

  10. ISPASSIVE – If the value chosen is yes, then the Oracle server under consideration is a passive server in an Oracle cluster. No alerts will be generated if the server is not running. Measures will be reported as “Not applicable’ by the agent if the server is not up.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Allocated size of database:

Indicates the amount of space currently allocated to the datafiles for use.

GB

 

Used space in allocated:

Indicates the amount of allocated space currently used by the datafiles.

GB

 

Free space in allocated:

Indicates the amount of allocated space that is still unused by the datafiles.

GB

 

Space usage in allocated:

Indicates the percentage of allocated space that has been utilized by the datafiles.

 

Percent

If the use max size parameter of this test has been set to No, then the value of this measure will be computed using the following formula:

Used space/Total size of database * 100

If the use max size parameter of this test has been set to Yes, then the value of this measure will be computed using the following formula:

Used space/Maximum size upto which the database can grow * 100

Ideally, this value should be low. A value close to 100% is a cause for concern.

Free percentage in allocated size:

Indicates the percentage of allocated space that is unused.

Percent

 

Max size of database:

Indicates the maximum size upto which the shared cluster storage can grow.

GB

 

Used space in max size:

Indicates the amount of space used by datafiles.

GB

 

Free space in max size:

Indicates the amount of space that is still unused by datafiles.

GB

 

Space usage in max size:

Indicates the percentage of max space that is currently used by datafiles.

Percent

 

Free percentage in max size:

Indicates the percentage of max space that is available for use.

Percent

 

Space free:

Indicates the percentage of free space in this database instance.

 

Percent

If the use max size parameter of this test has been set to No, then the value of this measure will be computed using the following formula:

Free space/Total size of database * 100

If the use max size parameter of this test has been set to Yes, then the value of this measure will be computed using the following formula:

Free space/Maximum size upto which the database can grow * 100

Ideally, this value should be high. A sudden/consistent decrease in the value of this measure could indicate excessive utilization of the database caused by a sporadic/steady increase in database activity. Very low free space in a database instance could significantly deteriorate its performance. Under such circumstances therefore, you might want to check the measures reported by the Oracle Datafile GrowthTest to figure out which datafile is consuming too much space. You might then want to resize the datafile.