Each dSource has its own data management settings, which can be configured during the linking workflow as well as in the configuration page for that dSource.

You can configure data management settings to improve overall performance and match the needs of your specific server and data environment.

The following settings are available for Oracle data sources:

Setting

Explanation

Initial Load

By default, the initial load takes place upon completion of the dSource linking wizard. 

Alternatively, you can set the initial load to take place according to a SnapSync policy. This might be desirable if you want the initial load to take place when the source database is under a lower load.

External Data Directory

An optional directory on the database server containing extra files associated with the database that are not included in normal SnapSync snapshots, for example, external table data files. Nothing in this directory will be modified, but the files will be loaded and provisioned along with the database.

Compression

Enable compression of backup data sent over the network. 

Compression is enabled by default.

Bandwidth Limit

Select the network bandwidth limit in units of MB/s between the source and the Delphix Engine. The default is 0, indicating that no bandwidth limit is enforced.

Number of Connections

Select the number of TCP connections to use between the Source and the Delphix engine.
Multiple connections may improve network throughput especially over long distances and highly congested networks. The default is 1.

Encrypted Linking

Turn on encryption between the source and the Delphix Engine. Enabling encrypted linking leads to higher CPU utilization and higher throughput.

Encrypted Linking is disabled by default.

Data Load Channels

The channel settings determine the number of channels and data files per backup set. While these settings can be increased, you should consider potential adverse effects on the performance of database operations on the Source server

  • Number of Channels - set the number of RMAN channels used during SnapSync. The default is 2.
  • Files per Channel - maximum number of data files in a backup set. The default is 5.

The product of files-per-channel and number of channels determines the maximum number of data files concurrently backed up by RMAN. 

Block Checking

Enable logical block validation by RMAN. Checking is CPU intensive and will slow down SnapSync. Enabling block checking will detect logical inconsistencies while syncing with the source.

Block checking is disabled by default.

Level Backup

Level backups should only be used to workaround Oracle bug 10146187 on physical standby sources. Switching from SCN to LEVEL mode will force a Level 0 backup. 

See Linking Oracle Physical Standby Databases for more information. Level Backups are disabled by default.

Skip Available Space Check

Skips checks for available space during the initial load in the Delphix Engine. The initial load will fail if the database needs more space than what is available in the Delphix Engine.

This setting is only recommended after consulting with Delphix Support

Double SnapSync

Double SnapSync, or DoubleSync, takes two snapshots sequentially in order to improve the performance of subsequent operations, such as VDB provisioning and refresh.

Performs the initial load without retrieving any archived logs, thereby creating a non-provisionable snapshot. At the completion of the initial load a second SnapSync that will retrieve logs will start. For more information, view the KB article.

LogSync Policy Settings

LogSync Policy Settings are available after the dSource has been added. In the Configuration page, you can select the following options:

  • Enabled - LogSync fetches log files from the source database, enabling the ability to provision a VDB from a specific point in time or, a database change number (SCN in the case of Oracle databases). LogSync must be enabled for this provisioning functionality to work. 
  • Archive Only, Archive and Online Redo - these settings determine whether LogSync fetches logs from archive storage in the source database file system, or both the file system and online redo logs. Online Redo mode is not supported for physical standby or RAC databases. It is also not supported if the online redo logs are raw devices or Oracle Automatic Storage Management devices. If LogSync detects any of the restricted cases it will automatically enter into Archive Only mode, regardless of the mode that was chosen. Additionally, Online Redo mode is not supported for mounted but not open primary databases.

LogSync policy settings for Oracle pluggable databases must be set at their corresponding container databases.

Validated Sync

Oracle validated sync is disabled by default. When enabled, validated sync is performed immediately after every subsequent SnapSync. See Enabling Validated Sync for Oracle for more information.

Note: Validated sync for Oracle pluggable databases is not supported in this release

Snapshot Parameters

There are also parameters you can specify when creating a snapshot of an Oracle data source. These parameters are explained in the table below.

ParameterExplanation

Force Full Backup

The Delphix Engine will by default perform an incremental backup, if for some reason a full backup is required (most often to resolve issues with datafile corruption), this option should be used.

Double Sync

Double SnapSync, or DoubleSync, takes two snapshots sequentially in order to improve the performance of subsequent operations, such as VDB provisioning and refresh.

Performs the initial load without retrieving any archived logs, thereby creating a non-provisionable snapshot. At the completion of the initial load a second SnapSync that will retrieve logs will start. For more information, view the Using the Double Sync option for Oracle SnapSync.

Do Not Resume

During the initial SnapSync, if a failure is encountered, the Delphix Engine can resume the SnapSync at a later date, this option will cause the engine to not resume, but rather to start the initial SnapSync over again.

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