Create Oracle Incremental-Forever Backups via RMAN - Data Disaster Recovery - Alibaba Cloud - Data Management

Database Backup Service (DBS) provides a true incremental-forever backup feature for Oracle. This feature uses a combination of full backups and synthetic backups to reduce backup costs and resource overhead.

Background information

The true incremental-forever backup feature for Oracle works as follows:

A full backup (RMAN level 0 backup) backs up all data files, archive logs, parameter files, and control files of the Oracle database.
A synthetic backup involves the following steps:
1. DBS creates a snapshot of the previous full backup set (either a full backup or a synthetic backup) and mounts it as a clone to a local self-managed database by using FUSE (Filesystem in Userspace).
2. An incremental backup backs up the data blocks that have changed since the last backup (a full backup or a synthetic backup). The changes are saved as an incremental backup file.
3. Data is synthesized. DBS runs the RMAN RECOVER COPY OF DATABASE WITH TAG 'dbs-specific-tag' command to read the incremental backup data from the previous step and merge it with the full backup data. The synthesized result overwrites the existing full backup data.
  
  Note
  The new synthesized backup set does not affect the previous full backup set.
4. The mount point on the local self-managed database is then unmounted.

Note

You can configure the weekly frequency of full backups in DBS. DBS performs one full backup each week, and all other backups run as synthetic backups. After a full backup is completed, it serves as the starting point for that week's synthetic backups.

Synthetic backups produce the same results as full backups and offer the following advantages:

Reduced backup costs: Synthetic backups minimize the data backed up, stored, and transferred, which lowers network bandwidth requirements.
Reduced resource overhead: They require fewer disk IOPS from the source database compared to a full backup.
Mount support: You can mount backup data for recovery in seconds.

Prerequisites

The Oracle database version is 11 to 19.
The Oracle database must use a single-instance or RAC architecture. The Oracle Data Guard physical standby architecture is not supported.
The server that hosts the Oracle database runs a Linux operating system, and a backup gateway is installed on the server. For more information, see Install a backup gateway.
FUSE is installed on the server.
Archive log mode must be enabled for the Oracle database. For more information, see Enable archive log mode.
You must have the Oracle SID. For more information, see Obtain the Oracle SID.
Block Change Tracking must be enabled.
Note
1. You can run the SELECT status FROM v$block_change_tracking; command to check whether Block Change Tracking is enabled. This feature is disabled by default.
  
  If the command returns ENABLED, the feature is enabled. If it returns DISABLED, the feature is disabled.
2. You can run the following SQL command to enable Block Change Tracking:
```
ALTER DATABASE ENABLE BLOCK CHANGE TRACKING USING FILE <path_of_the_block_change_tracking_file> REUSE;
```

Public preview

This feature is in public preview. To apply for access, search for and join the DingTalk group 35585947.

For Oracle backup schedules created during the public beta period, the only supported Backup set mode. is Sandbox instance mount backup. The sandbox feature is enabled by default, and you can create a free sandbox instance for the backup schedule during the public beta period. For more information, see DBS sandbox feature overview.

Note

The sandbox feature cannot be disabled during the public preview period.

Step 1: Create a backup schedule

For more information, see Create a backup schedule.

Note

When you create the backup schedule, set Database Type to Oracle and Backup Method to physical backup.

Step 2: Configure the backup schedule

Log on to the Data Management (DMS) console V5.0.
In the top navigation bar, choose Security and disaster recovery (DBS) > Data Disaster Recovery (DBS) > Backup Plan.

Note
If you use the DMS console in simple mode, move the pointer over the icon in the upper-left corner of the DMS console and choose All Features > Security and disaster recovery (DBS) > Data Disaster Recovery (DBS) > Backup Plan.
On the Backup Schedules page, find the backup schedule that you want to configure and click Configure Backup Schedule in the Actions column.

On the Configure Backup Source and Destination page, configure the backup source and destination, and then click Next.

Category	Parameter	Description
N/A	Backup schedule name	DBS automatically generates a name. Specify a descriptive name for easy identification. The name does not need to be unique.
Backup source	Backup method	This parameter is automatically set to the backup method you selected when creating the backup schedule. This topic uses physical backup for Oracle.
	Instance region	Select the region where the target database instance is located.
	Backup gateway	Select the backup gateway for the target database. For information about how to add a backup gateway, see Install a backup gateway.
	Database type	Defaults to Oracle.
	SID	Enter the Oracle SID of the target database. For more information, see Obtain the Oracle SID.
	Log on to database	Enter the SQLPlus command to log on to the database. Format: `username/password@instance_name as sysdba`. Example: `sys/password@orcl as sysdba`. Note* You can also enter `/ as sysdba`. However, this command fails if operating system authentication is disabled in your database environment.
	Oracle home	Enter the absolute path of ORACLE_HOME. For more information, see Obtain the database program directory. Note This parameter is optional.
	Data security and cross-border data transfer commitment	Read and select the commitment checkbox.
Backup destination	Storage type	The storage type for the backup destination. Valid values: DBS built-in storage (Recommended): Data is automatically stored in DBS built-in storage, so you do not need to create a storage space. You are charged based on the amount of data stored in DBS. For more information, see Storage fees. OSS For User: You must create an Object Storage Service (OSS) bucket in advance. For more information, see Create a bucket. Note This topic uses DBS built-in storage as an example. If you select User OSS, you must also configure the OSS bucket name parameter. Only the OSS Standard storage class is supported. If you have a large amount of data, we recommend that you purchase a DBS storage plan (subscription) to offset the costs of DBS built-in storage. Storage plans are more cost-effective than the pay-as-you-go billing method.
Backup destination	Storage encryption	The encryption method for stored data. Valid values: Encrypted (Recommended): Encrypts data by using the industry-standard AES-256 algorithm. OSS encrypts objects upon upload and automatically decrypts them upon download. For more information, see Server-side encryption. Non-encrypted: Data is not encrypted.

In the Edit Backup Objects step, Back Up Entire Instance is selected by default. Click Next.
Note
If you back up an entire database, the permission data and stored procedures are also backed up.

On the Configure Backup Time page, configure the backup time and other settings, and then click Next.

Parameter	Description
Full backup frequency	Select Periodic Backup or Single Backup. Note If you select Periodic Backup, you must configure the Full Data Backup Recurrence, Start At, and Real-Time Transaction Log Backup parameters.
Full backup period	The days of the week on which DBS runs the backup schedule. You can select one or more days of a week. Select at least one day of the week.
Start time	The start time of the backup. We recommend that you specify a point in time during off-peak hours. Example: 01:00. Note If a previous full data backup is not finished at the start time of the next backup, DBS skips the next backup.
Incremental backup	Specifies whether to enable incremental backup.
Max concurrent threads for full backup	The maximum number of concurrent threads that are available for a full backup. You can configure this parameter to adjust the backup speed. For example, you can reduce the number of backup threads to minimize impacts on the database.
Backup network throttling	The limit on the network bandwidth. You can specify the limit based on your business requirements. Default value: `0`, which indicates that the network bandwidth is not limited. Note When backing up a production database, configure a network speed limit as needed to reduce the impact on the production database.
Incremental backup interval	The interval at which incremental backup is performed. DBS performs incremental backup based on your configurations. If you set the interval to 10 minutes, DBS performs an incremental backup every 10 minutes.
Delete log after successful backup	Specifies whether to delete successfully backed-up archive logs from the self-managed database. If you select Yes, you must also configure the Retain archive log for (days) parameter.
Retain archive log for (days)	The number of days to retain archive logs on the self-managed database. After a successful backup, the system deletes logs that are older than this specified retention period. The default value is 7, which means archive logs older than 7 days are deleted. This parameter is displayed only when Delete log after successful backup is set to Yes.
Enable compression	Specifies whether to compress backup data. Valid values: Enable: recommended. Data is compressed during backup to reduce storage space. Disable: Data is not compressed during backup.
Backup set mode	Only the Sandbox instance mount backup mode is supported. RMAN performs an Image Copy backup, and the backup data is streamed to OSS through the FUSE protocol without being written to disk. If the DBS sandbox feature is enabled, backup data can be mounted in seconds. Your server must have FUSE installed. Otherwise, the backup fails.

On the Edit Lifecycle page, specify the retention period for full backup data in DBS built-in storage.

If you enabled the Incremental backup feature in the previous step, you must also configure the retention period for incremental backup data. For more information about the backup data lifecycle, see Manage the lifecycle of backup data.
After the preceding configurations are complete, click Precheck in the lower-right corner of the page.
After the precheck passes, click Start Now in the confirmation dialog box.

What to do next

Data Disaster Recovery supports restore to a different server, restore to a different location on the source server, and restore to the original location on the source server. For more information, see Restore an Oracle database from a physical backup.