Using Delphix as a Backup Solution to SQL Server

Delphix provides you the option to automatically manage backups from SQL Server source databases into the Delphix Engine. Prior to Delphix 4.2, users could not link source databases that were backed up by an unsupported backup software. In Delphix 4.2, a feature known as Delphix Managed Backups was introduced that allows you to have Delphix take and manage backups from your source database directly into Delphix storage. This is the first step in Delphix becoming a full-featured backup solution for SQL Server databases. When the Delphix Engine manages the backups for a dSource, it takes regular, copy-only full backups of the source database, so activating the feature will not interfere with existing backup management solutions. You can configure the schedule of when the Delphix Engine takes these copy-only full backups by specifying a SnapSync policy for the dSource. You can change the SnapSync policy for a dSource at any time by visiting the policy screen; there, you can either select a new SnapSync policy or modify the current one.

If you use a backup solution that is not supported by Delphix, you cannot use your existing backups to keep your dSources in sync. However, enabling Delphix Managed Backups will overcome this issue by using automatic copy-only full backups to keep dSources in sync. Currently, dSources linked when this feature is enabled will not support LogSync functionality, which means that you can only provision VDBs from snapshots and not from any time between snapshots. Additionally, in the current release, the Delphix Engine cannot take differential or transaction log backups of the source database.

Linking SQL Server dSources with Delphix Managed Backups

The Data Management page of the link wizard for SQL Server dSources provides the option to enable Delphix Managed Backups.

It possible to enable this feature here at link time or toggle it on after the link for future syncs. If you enable this feature, the dSource can only use copy-only full backups taken by the Delphix Engine to stay in sync with its source; the Delphix Engine will prohibit syncing using existing backups. Checking the Enabled box results in the following changes to the Data Management page:

  • The initial load option is set to a copy-only full backup taken by the Delphix Engine
  • The ability to provide a backup path disappears
  • A SnapSync policy selection screen appears in the Policies page

You can select from the list of existing SnapSync policies, if the one you want doesn't exist you will need to create a new one on the Policies page under the Manage dropdown. Proceeding through the remainder of the link wizard will create a dSource with Delphix-managed backups enabled. You can confirm that a dSource has the feature by selecting the dSource and going to the  Configuration > Data Management tab after creation and checking the Delphix Managed Backups section, as displayed below:

To disable / enable this feature after linking:

Toggling Delphix Managed backups is supported for SQL Server dSources. This means a dSource that was previously created with Delphix Managed Enabled can have regular validated sync and similarly a dSource that had external backups can use Delphix Managed Backups.

To disable Delphix Managed Backups for a specific dSource, select that specific dataset and go to Data Management tab under the Configuration tab. 

Click the edit button and uncheck this feature. Then update all new inputs.

To enable this feature just go to the same edit menu.

Understanding SnapSync Policies

SnapSync policies provide you the ability to specify how frequently the Delphix Engine takes a copy-only full backup of a source database when Delphix Managed Backups are enabled. Selecting an initial SnapSync policy is mandatory at dSource link time. However, you can change the SnapSync policy that the Delphix Engine applies to a dSource at any time by visiting the policy management screen:
  1. Click Manage.
  2. Click Policies.

Check SnapSync Policy

For dSources that have Delphix-managed backups enabled, the current SnapSync policy will be displayed under the SnapSync column. The rows corresponding to dSources that do not use Delphix Managed Backups will be grayed out. Clicking the current SnapSync policy for a dSource will display a drop-down menu of existing SnapSync policies along with the option to create a new SnapSync policy. Selecting a SnapSync policy from this list will change the current SnapSync policy for the dSource. When creating a new policy, you will see the following screen:

Create New SnapSync Policy

Here, you can configure the frequency with which the Delphix Engine takes backups of your source database. You can modify these schedules at any time by clicking the Modify Policy Templates button in the upper right-hand corner of the policy management screen.

The Timeout field above specifies how long a SnapSync job is allowed to run before it is terminated. If a SnapSync job exceeds its timeout window, the Delphix Engine discards the new backup and rolls back the dSource to the most recent snapshot.

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