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Oracle init Parameters and Delphix

By Shailendra Upadhyay posted 09-28-2015 04:36:01 PM


                                               Oracle init Parameters and Delphix

When provisioning a VDB (virtual database), by default, Delphix uses the source database’s init.ora parameters. During provisioning, Delphix uses three sets of parameters, listed below, for filtering when provisioning a VDB.

Customizable Parameters with Oracle Default Values:

The value for these parameters is set to default during the provisioning process; these parameters are removed from the VDB configuration file unless you set values for them during the provisioning of the VDB. These values can be set in the provision wizard or through using a VDB Config Template. Delphix resets these parameter values because they are generally applicable for a specific databases, and therefore it is meaningless to copy the values from the source database to the VDB.  Here are some of the most commonly used customizable parameters:

·    audit_file_dest

·    diagnostic_dest

·    log_archive_dest_1

·    log_archive_dest_state_1

·    remote_listener

For the complete list of customizable parameters see Customizing Oracle VDB Configuration Settings.

Customizable Parameters with Source Values:

Delphix allows for the below parameters to be customized to your specific needs for your Oracle database:

·    sga_target

·    open_cursors

For the complete list of customizable parameters see Customizing Oracle VDB Configuration Settings.

Restricted Parameters:

These parameters are restricted for use by the Delphix Engine, attempting to customize these parameters through the use of a VDB Configuration Template will cause an error during the provisioning process. For the complete list of restricted parameters see Customizing Oracle VDB Configuration Settings.

Note: If you try to use one of these parameters you might see this error:


One or more parameters that are reserved have been provided: [restricred_parameter_name]

Suggested Action:

Remove parameters and try again.

VDB Provision and init Parameters:

When a VDB is provisioned without using a VDB Config Template, we can change configuration parameters (i.e. sga_target or db_cache_size) by clicking the Advanced link in the Target Environment screen in the Provision VDB wizard. While using default settings, Delphix will inherit the source database parameters that have been captured with the SnapShot (Note: Delphix captures all non-default parameters from a source database with a Snapshot.) During a routine provision, Delphix inherits init parameters listed from parent Snapshot, removes everything from the 'restricted list' and the 'customizable list', then presents it to the user; once that is complete the provisioner can edit available parameters as per their internal requirements- as long as they are not in conflict with above mentioned restricted parameters.

If you are edit parameters more than once, you can create a VDB Config Template to expedite this process. You can create a VDB Config Template by clicking the Manage > VDB Config Templates option in the GUI to specify new parameters values for a VDB. If you use a VDB Config Template, Delphix ensures that no restricted parameter is input into the config template, also, default values will be used for any parameter which is not specified explicitly in config template.

VDB Refresh and init Parameters:

If you are using VDB Config Template for provisioning, Delphix will apply all the config template parameters during a refresh as well. VDB Config Templates override any parameter changes made after provisioning (ex: alter system set open_cursors=new_value). Delphix recommends updating VDB Config Template with new parameter value if you plan to use new values for future refresh/provisioning operations.

Note: If you are refreshing a VDB with no VDB Config Template associated with it, Delphix will preserve the current parameter values of the VDB after the refresh. The current parameter values of a VDB are the set of values captured at the time of the most recent VDB Snapshot.

VDB Rewind and init Parameters:

If you rewind a VDB, Delphix will use init parameter values from the VDB Snapshot that the rewind originates from unless you have specified a Config Template to apply to the VDB after the rewind.