When linking a dSource, you can use custom data management settings to improve overall performance and match the needs of your specific server and data environment. If you do not require any specific settings, leverage default data management settings.
Accessing Data Management Settings
There are three ways to set or modify data management settings for dSources:
During the dSource linking process:
- In the Data Management panel of the Add dSource wizard, click Advanced.
- For more details, refer to Linking a dSource.
On the Configuration tab of the Datasets details page:
- Login to the Delphix Management application using delphix_admin credentials or another account with admin privileges.
- In the top menu bar, click Manage.
- Select Datasets.
- Select a dSource.
- Click the Configuration tab in the center pane.
- Select the Policies sub tab, from the drop-down menu next to the SnapSync Policy and Retention Policy fields select a policy.
- Policies are created by selecting Manage > Policies.
- Click the pencil icon next to a policy to modify.
- To add a new policy, click the plus sign icon labeled Apply New Policy. For more information, refer to the instructions for Managing Policies, if necessary.
In the top menu bar:
- Click Manage.
- Select Policies. This will open the Policy Management screen.
- In the Policy Management screen, select the policy for the dSource you want to modify.
- In the pop-up dialog, click the pencil icon to modify.
- To add a new policy, click the Orange button located on the top right. For more information, refer to the instructions for Managing Policies, if necessary.
Retention policies define how long the Delphix Engine retains snapshots and log files to which you can rewind or provision objects from past points in time. The retention time for snapshots must be equal to, or longer than, the retention time for logs.
To support longer retention times, you may need to allocate more storage to the Delphix Engine. The retention policy – in combination with the SnapSync policy – can have a significant impact on the performance and storage consumption of the Delphix Engine.
Oracle Pluggable Database
For Oracle 12c Multitenant support, Delphix allows users to take snapshot from a pluggable database but not a container database. The snapshot retention policy is therefore only applicable to a pluggable database but not a container database.
Oracle 12c Multitenant architecture shares redo logs across all pluggable databases. The container database owns the redo logs. As a result, the log retention policy is only applicable to a container database, but not a pluggable database.
Benefits of Longer Retention
With increased retention time for snapshots and logs, you allow a longer (older) rollback period for your data.
Common use cases for longer retention include:
- Frequent application changes and development
Caution and controlled progression of data
Reduction of project risk
- Speed of rollback or restoring to older points in time
You can customize the retention policy to retain snapshots and logs for longer periods of time, enabling provisioning, refresh, and rewind for either to snapshots or (if LogSync is enabled) to specific points-in-time further back in time.
Oracle Initial Load Options
The SnapSync policy determines how often snapshots are taken of the source database. In the Default SnapSync policy, a snapshot is taken daily at 3:30 AM local time, and will time-out after four hours. If SnapSync does not complete within this four hour period, it will resume at the next scheduled daily time, until the process is complete. Click the Edit icon to change the Default SnapSync policy, or click the Add icon to create a new SnapSync policy. See Creating Policy Templates for more information.
Oracle LogSync Policy Settings
- 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. LogSync is disabled if the source database is detected to be mounted but not open.
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.
LogSync for Oracle Standby Databases
LogSync must be enabled for Oracle physical standby databases in Level Backup mode and using Real Time Apply. See Linking Oracle Physical Standby Databases.
LogSync for Oracle Pluggable Databases
LogSync policy settings for Oracle pluggable databases must be set at their corresponding container databases.
Oracle Validated Sync Settings
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.
Oracle Pluggable Database
Validated sync for Oracle pluggable databases is not supported in this release
Oracle Sync Options Settings
- Compression - enable compression of backup data sent over the network. Default is Enabled.
- Bandwidth Limit - select the network bandwidth limit in units of MB/s between Source and Delphix Engine. Default is 0, or no bandwidth limit enforced.
- Number of Connections - select the number of TCP connections to use between Source and Delphix Engine.
Multiple connections may improve network throughput especially over long distance and highly congested networks. Default is 1.
- Encrypted Linking - turn on encryption between Source and Delphix Engine. Default is Disabled.
- 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. Default is 2.
- Files per Channel - maximum number of data files in a backup set.
The product of files-per-channel and channels determines the maximum number of data files concurrently backed up by RMAN. Default is 5.
- Block Checking - enable logical block validation by RMAN. Checking is CPU intensive and will slow down SnapSync. Default is Disabled.
- Level Backup - enable LEVEL backup mode.
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. Default is Disabled or SCN Backup mode.