Oracle Dataguard Status Test

Oracle Database lets you save filled groups of redo log files to one or more offline destinations, known collectively as the archived redo log, or more simply the archive log. The process of turning redo log files into archived redo log files is called archiving. Data Guard manages the transmission of redo data using the Redo transport services.

Redo transport services control the automated transfer of redo data from the production database to one or more archival destinations.

Redo transport services perform the following tasks:

  • Transmit redo data from the primary system to the standby systems in the configuration
  • Manage the process of resolving any gaps in the archived redo log files due to a network failure
  • Enforce the database protection modes
  • Automatically detect missing or corrupted archived redo log files on a standby system and automatically retrieve replacement archived redo log files from the primary database or another standby database.

There are several types of destinations supported by redo transport services. They are:

  • Oracle Data Guard standby databases
  • Archived redo log repository
  • Oracle Streams real-time downstream capture database
  • Oracle Change Data Capture staging database

If the destination at which the redo logs have to be archived is not available, then there would be a considerable difference in the data stored between the production database and the standby databases. To avoid such indifferences and maintain proper synchronization of data, it is essential to monitor the status of the destination at which the log files are archived constantly. The Oracle Dataguard Status test helps administrators in this regard!

For each destination at which the redo logs are to be archived, this test reports the current status of the destination and the current applied mode of the destination.

Target of the test : An Oracle server on which Data Guard feature is enabled

Agent deploying the test : An internal/external agent

Outputs of the test : One set of results for each destination to which the redo log files are to be archived from the target Oracle Database server being monitored.

Configurable parameters for the test
  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. 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.

  5. 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.

  6. Confirm password – Confirm the password by retyping it here.
  7. 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.
  8. includepath - This test reports a set of results for each datafile on the target Oracle database server. This means that every datafile is a descriptor of this test. By default, while displaying the descriptors of this test, the eG monitoring console does not prefix the datafile names with the full path to the datafiles. This is why, the INCLUDE PATH flag is set to No by default. If you want the data file names to be prefixed by the full path to the data files, then, set the INCLUDE PATH flag to Yes.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Status

Indicates the current status of this archived redo log destination.

 

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Valid 0
Alternate 1
Diferred 2
Full 3
Error 4
Disabled 5
Bad param 6

Note:

By default, this measure reports the current status of each archived redo log destination. The graph of this measure however, is represented using the numeric equivalents only - 0 to 5.

Recovery mode

Indicates the current applied mode on this archived redo log destination.

 

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Managed 0
Managed real time apply 1
Logical real time apply 2
Logical apply 3
Idle 4

Note:

By default, this measure reports the current applied mode of the archived redo log destination. The graph of this measure however, is represented using the numeric equivalents only - 0 to 4.