This topic describes advanced data management settings for dSources.
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 no specific settings are required, 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, click Advanced in the Data Management panel of the Add dSource wizard.
- On the back of the dSource card, click the field next to Retention Policy under Data Management. Click the Edit icon.
For SnapSync and Retention policies, click the policy name. This will open the Policy Management screen.
- Select Manage > Policies in the top menu bar.
This will open the Policy Management screen. Select the policy for the dSource you want to modify, and click Modify.
For more information, see Creating Custom Policies and Creating Policy Templates.
Retention policies define the length of time 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.
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:
With logsync enabled, you can customize both the retention policy and the SnapSync policy to access logs for longer periods of time, enabling point-in-time rollback and provisioning.
LogSync for SQL Server dSources
LogSync is disabled by default for SQL Server dSources because snapshots are triggered by transaction log backups of the source database taken by the user, rather than SnapSync policies. On average, transaction log backups are taken every 30 minutes to an hour, resulting in frequent snapshots. LogSync should be enabled if there is a need to be able to provision to a finer granularity than is possible using transaction log backups. Enabling LogSync will increase the storage required for the dSource on the Delphix Engine because the Delphix Engine will start storing the transaction log backups according to the log retention policy.
LogSync settings are accessible during the Add dSource process and on the back of the dSource card.
- Enabled - LogSync adds log files from the source database to the dSource, enabling the ability to provision a VDB from a specific point in time or LSN for SQL Server databases. LogSync must be enabled for this provisioning functionality to work.