Traditional Database Backup TechniquesWeekly Full and Daily Incremental BackupsOne popular approach, shown in Figure 1-1, is to use RMAN to take a weekly full backup, and then daily incremental backups. To improve incremental backup performance, Oracle recommends enabling block change tracking. These backups occur when activity on the database is lowest. Show
An advantage of this technique is that backup windows, which affect the production server, are relatively brief on the days when incremental backups occur. A disadvantage is that when the database is continuously active, as when serving multiple global time zones, no easily accommodating backup window is available. One solution is to set up Oracle Data Guard, and then back up the standby database, thereby removing the backup load from the production server. However, protecting all databases with Oracle Data Guard is often impractical. Incremental Backups and RECOVER COPYThe RMAN technique shown in
Figure 1-2 makes daily incremental backups, and then uses the This technique has the following advantages:
Some disadvantages are as follows:
Full Backups to a Third-Party Deduplicating ApplianceAs an alternative to RMAN incremental backups and tape drives, some customers use third-party deduplicating appliances to process backup streams. Figure 1-3 depicts three databases writing to a centralized third-party appliance. This technique has the following advantages:
Some disadvantages are as follows:
Third-Party Storage SnapshotsA
third-party storage snapshot is a set of pointers to storage blocks (not Oracle blocks) that existed when the snapshot was created. The virtual copies reside on the same storage array as the original data.
Figure 1-4 depicts a copy-on-write snapshot, which is a type of third-party snapshot. After a snapshot is taken,
when the first change to a storage block occurs, the array copies the before-image block to a new location on disk ( This technique has the following advantages:
Some disadvantages are as follows:
Data Protection Challenges in the Modern EnterpriseThe role of information technology in the modern business is going through a tremendous transformation. The key drivers for this transformation are:
The protection strategies described in "Traditional Database Backup Techniques" are not designed to solve the challenges created by this transformation. Enterprises find themselves without a consistent backup and recovery strategy. The following shortcomings are common to most or all of the traditional backup techniques:
The traditional techniques fail to provide a comprehensive and efficient Oracle-integrated data protection solution that meets the demands of a large-scale, enterprise Oracle environment. A new approach is required. Oracle's Recovery Appliance SolutionRecovery Appliance is a cloud-scale Engineered System designed to protect all Oracle databases across the enterprise. Most database backup and restore processing is performed by the centralized Recovery Appliance, making storage utilization, performance, and manageability of backups more efficient. The Recovery Appliance stores and manages backups of multiple Oracle databases in a unified disk pool, using an RMAN incremental-forever strategy. The Recovery Appliance continually compresses, deduplicates, and validates backups at the database block level, while creating virtual full backups on demand. A virtual full backup is a complete database image as of one distinct point in time, maintained efficiently through Recovery Appliance indexing of incremental backups from protected databases. A virtual full backup can correspond to any incremental backup that was received. Figure 1-5 shows an overview of a sample Recovery Appliance environment. As shown in Figure 1-5, a protected database is a client database that backs up data to a Recovery Appliance. Each protected database uses the Zero Data Loss Recovery Appliance Backup Module (Recovery Appliance Backup Module) for its backups. This module is an Oracle-supplied SBT library that RMAN uses to transfer backup data over the network to the Recovery Appliance. The Recovery Appliance metadata database, which resides on each Recovery Appliance, manages metadata stored in the RMAN recovery catalog, and backups located in the Recovery Appliance storage location. The catalog is required to be used by all protected databases that send backups to Recovery Appliance. Note: Databases may use Recovery Appliance as their recovery catalog without also using it as a backup repository. Administrators use Oracle Enterprise Manager Cloud Control (Cloud Control) to manage and monitor the environment. Cloud Control provides a "single pane of glass" view of the entire backup lifecycle for each database, whether backups reside on disk, tape, or another Recovery Appliance. Recovery Appliance provides the following benefits:
Elimination of Data LossProtection of Ongoing TransactionsIn traditional backup approaches, if the online redo log is lost, then media recovery loses all changes after the most recent available archived redo log file or incremental backup. A recovery point objective (RPO) of a day or more that might result from a traditional approach may be unacceptable. Recovery Appliance solves the RPO problem through a continuous transfer of redo changes to the appliance from a protected database. This operation is known as real-time redo transport. Using delta push, the Recovery Appliance is a remote destination for asynchronous redo transport services from Oracle Database 11g and Oracle Database 12c databases. Note: This technology is based on the real-time redo transport algorithms of Oracle Data Guard. To avoid degrading the performance of the protected database, protected databases transfer redo asynchronously to the Recovery Appliance. If a protected database is lost, zero to subsecond data loss is expected in most cases. See Also:
Secure ReplicationTo protect against server or site outage, one Recovery Appliance can replicate backups to a different Recovery Appliance. Figure 1-6 shows the simplest form of replication, called one-way Recovery Appliance replication, in which an upstream Recovery Appliance (backup sender) transfers backups to a downstream Recovery Appliance (backup receiver). In Figure 1-6, a protected database sends an incremental backup to the Recovery Appliance, which then queues it for replicating to the downstream Recovery Appliance. When the upstream Recovery Appliance sends the incremental backup to the downstream Recovery Appliance, it creates a virtual full backup as normal. The downstream Recovery Appliance creates backup records in its recovery catalog. When the upstream Recovery Appliance requests the records, the downstream Recovery Appliance propagates the records back. If the local Recovery Appliance cannot satisfy virtual full backup requests, then it automatically forwards them to the downstream Recovery Appliance, which sends virtual full backups to the protected database. DBAs use RMAN as normal, without needing to understand where or how the backup sets are stored. Autonomous Tape ArchivalA robust backup strategy protects data against intentional attacks, unintentional user errors (such as file deletions), and software or hardware malfunctions. Tape libraries provide effective protection against these possibilities. Figure 1-7 show the traditional technique for tape backups, with a media manager installed on each host. Figure 1-8 shows the Recovery Appliance technique for tape backups. The fundamental difference in the two approaches is that the Recovery Appliance backs up to tape, not the protected databases. The Recovery Appliance comes with preinstalled Oracle Secure Backup software, and supports optional Fibre Channel cards. Thus, installation of a media manager is not necessary on the protected database hosts. When Recovery Appliance executes a copy-to-tape job for a virtual full backup, it constructs the physical backup sets, and copies them to tape, and then writes the metadata to the recovery catalog. If desired, the Recovery Appliance can also copy successive incremental backups and archived redo log file backups to tape. Whereas the backup on the Recovery Appliance is virtual, the backup on tape is a non-virtual, full physical backup. The Recovery Appliance automatically handles requests to restore backups from tape, with no need for administrator intervention. The advantages of the Recovery Appliance tape solution are as follows:
End-to-End Data ValidationA basic principle of backup and recovery is to ensure that backups can be restored successfully. To ensure that there are no physical corruptions within the backed-up data blocks, backups require regular validation. Validation typically involves running an RMAN RESTORE VALIDATE job regularly, along with running periodic full restore and recovery operations to a separate machine. Recovery Appliance provides end-to-end block validation, which occurs in the following stages of the workflow:
None of the preceding backup validation processes occur on the production database hosts, thus freeing production resources for more critical operational workloads. Note: Oracle Maximum Availability Architecture best practices recommend that you still perform periodic full database recovery tests to verify operational practices and to detect issues that might occur only during media recovery. See Also:
Minimal Backup OverheadIn traditional database backup techniques, the Oracle database host performs the brunt of the processing. Agents for disk backup, tape backup, and deduplication may all be running on the host. Furthermore, all backup operations—compression, validation, deletion, merging, and so on—occur on the database host. This overhead can greatly degrade database performance. Recovery Appliance removes almost the entire load from the protected databases. The only backup operations required on the hosts, which could be primary database or standby database hosts, are sending incremental backups to the Recovery Appliance. The incremental-forever strategy reduces the backup window on the database hosts significantly. Recovery Appliance handles backup processing, tape operations, data integrity checks, and routine maintenance. Note: Recovery Appliance only supports backups of Oracle databases, not file system data or non-Oracle databases. Recovery Appliance optimizes management of database changes using delta push and delta store, shown in Figure 1-9. The net result of delta push and delta store is that the problem of lengthening backup windows is eliminated. The DBA performs only fast incremental backups, and lets the Recovery Appliance manage the backup blocks. Delta PushThis solution consists of two operations that run on each protected database: the incremental-forever backup strategy, and real-time redo transport. Both operations involve protected databases pushing changes to the Recovery Appliance. In an incremental-forever strategy, only one incremental level 0 backup to the Recovery Appliance is required in the lifetime of each protected file. The initial level 0 backup does not contain committed undo blocks or currently unused blocks. Note: The elimination of committed undo and currently unused blocks is only supported for SBT full backups to the Recovery Appliance or Oracle Secure Backup. It is not available for SBT backups to other backup products. In normal operation, the Recovery Appliance automatically performs the following steps for each incremental level 1 backup:
The incremental-forever strategy greatly reduces the backup window and overhead because no full backups are ever required after the initial incremental level 0 backup. If the strategy includes real-time redo transport, then backup windows are further reduced because traditional archived log backups are not necessary. Also, Recovery Appliance takes on the burden of validation, deduplication, and compression. Note: Blocks compressed using table or Hybrid Columnar Compression remain compressed in the RMAN backup and during the Recovery Appliance ingest phase. Delta StoreThe delta store is the key processing engine for Recovery Appliance. A protected database sends only one incremental level 0 backup of each data file to the Recovery Appliance. Following the initial full backup, all backups are highly efficient cumulative incremental backups. As Recovery Appliance receives incremental backups, it indexes them and stores them in delta pools. Each separate data file backed up to the Recovery Appliance has its own separate delta pool (set of backup blocks). Recovery Appliance automatically manages the delta pools so that it can provide many virtual full backups. Creation of Virtual Full Backups To create a virtual full backup, Recovery Appliance converts an incoming incremental level 1 backup into a virtual representation of an incremental level 0 backup. A virtual full backup appears as an incremental level 0 backup in the recovery catalog. From the user's perspective, a virtual full backup is indistinguishable from a non-virtual full backup. Using virtual backups, Recovery Appliance provides the protection of frequent level 0 backups with only the cost of frequent level 1 backups. Note: Recovery Appliance provides storage services, but not virtual full backups, for RMAN-encrypted backups (see "Archival and Encrypted Backups"). These backups are stored in their original encrypted format. Recovery Appliance can store, archive, and retrieve them just as it can for unencrypted RMAN backup sets. Rapid Recovery Using Virtual Full Backups Recovery Appliance uses virtual full backups to provide rapid recovery to any point in time, regardless of the amount of data being recovered. The on-disk recovery strategy of Recovery Appliance has the advantage that RMAN can recover virtual full backups to any point in time without applying incremental backups. When a database is protected by the Recovery Appliance, RMAN must only restore a single level 0 backup for the day of the RPO, and then recover up to the last second using redo log files sent using the real-time redo transport feature. For example, if the recovery window is 7 days, and if the RPO is 5 days ago, then RMAN can restore a single virtual full (level 0) backup that is current to 5 days ago, and then recover it using redo—not level 1 incremental backups. See Also:
Improved End-to-End Data Protection VisibilityIn traditional database backup techniques, management of the database, media server, and tape drives are often separated. For example, a DBA group may manage the databases, while a separate backup administrator group manages the backups, and a storage group manages the disk and tape devices. The overall process lacks visibility, which makes it difficult to manage backups for thousands of databases, each with different recovery requirements. Cloud Control provides a complete, end-to-end view into the backup lifecycle managed by the Recovery Appliance, from the time the RMAN backup is initiated on the database, to when it is stored on disk, tape, or replicated to a downstream Recovery Appliance. Recovery Appliance monitoring and administration are enabled through installation of the Enterprise Manager for Zero Data Loss Recovery Appliance plug-in (Recovery Appliance plug-in). Using Cloud Control to manage a Recovery Appliance provides the following benefits:
Although Cloud Control is the recommended user interface for Recovery Appliance administration, Oracle supplies the See Also:
Cloud-Scale ProtectionPolicy-Based Data Protection ManagementRecovery Appliance simplifies management through the protection policy. Benefits include the following:
Database-Aware Space ManagementUsing protection policies, the Recovery Appliance manages backup storage space according to the recovery window goal for each protected database. This granular, database-oriented space management approach eliminates the need to manage space at the storage-volume level, as third-party appliances do. If space is available, then the Recovery Appliance may retain backups older than the recovery window goal, effectively extending the point-in-time recovery period. When space pressure exists, the Recovery Appliance uses predefined thresholds to purge backups. The Recovery Appliance automatically provisions space so that the recovery window goal for each database is met. Scalable ArchitectureThe approaches in "Traditional Database Backup Techniques" are prone to performance bottlenecks and multiplying points of failure. As the number of databases increases, so does the number of media servers, disk arrays, tape devices, and third-party appliances, and thus so does the overall complexity. The "add more devices" approach is not scalable. In contrast, Recovery Appliance can scale to accommodate increases in backup traffic, storage usage, and the number of databases by adding compute and storage resources in a simple, modular fashion. Maximum Availability: Recovery Appliance with Oracle Data GuardOracle Data Guard is a component of a high availability (HA) and disaster recovery solution that can be integrated with Recovery Appliance to provide maximum data protection. Oracle Data Guard minimizes service interruption and resulting data loss by maintaining a synchronized standby database for the protected database. When the primary system is unavailable, the standby immediately assumes the normal operations of the primary after a Data Guard failover operation, including backups to the local Recovery Appliance. Figure 1-10 shows an example of an environment with Recovery Appliance and Oracle Data Guard. In Figure 1-10, the primary and standby databases each send incremental backups to their local Recovery Appliance. The primary database sends real-time redo changes to both the local Recovery Appliance and the physical standby, and the standby cascades the redo changes to the remote Recovery Appliance. Each Recovery Appliance has backups and redo information for the same database, therefore either appliance can be used for RMAN restore and recovery operations. See Also:
What's Next?To begin using Recovery Appliance, refer to the following topics:
Which type of backup takes the least amount of time?Incremental backups take the least space and time to perform than differential and full backups, but it's the most time-consuming out of all of the methods to restore a full system.
What are 4 types of backups?Each backup program has its own approach in executing the backup, but there are four common backup types implemented and generally used in most of these programs: full backup, differential backup, incremental backup and mirror backup.
Which backup type will take the shortest time to restore?Full backups are the quickest to restore since all files are contained in the same backup set. Full backups typically provide the best protection against critical data loss, but they are often conducted periodically on a predetermined schedule because of the time and expense involved.
What type of backup requires the largest amount of storage space?Cons of Full Backups
Requires the most storage space. Demands the most bandwidth. Relatively time-consuming to complete the backup process.
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