Snapshots are generally implemented either as copy-on-write or redirect-on-write-based methods. Because of this tight physical relationship, the snapshot is maintained on the same storage array as the original data. Snapshots do not require an initial copy, as they are not stored as physical copies of blocks, but rather as pointers to the blocks that existed when the snapshot was created. Storage snapshots have offered development and QA capabilities for database and non-database environments for many years, providing the ability to quickly create point-in-time storage-efficient virtual copies of the data. The diagram below illustrates this backup strategy:įigure 1 – Oracle Suggested Backup Strategy This backup strategy is further enhanced when combined with the Fast Recovery Area (FRA), a single disk location where all recovery-related files (including RMAN backups) can be stored and automatically managed by Oracle, relieving the DBA from having to oversee backup space management tasks and ensuring that all needed recovery-related files are always available per the user-defined retention policy. For example, Oracle Database 10g Release 1 introduced incrementally updated backups, which allows a full image copy backup of a tablespace/datafile/database on disk to be updated in-place using a fast incremental backup - in effect, creating a more current full backup on disk in just the time it takes to apply the incremental. Since its debut in Oracle8, Recovery Manager (RMAN) has offered a rich and evolving set of database-optimized backup and recovery capabilities, fulfilling a wide range of data protection requirements. Overview – Recovery Manager (RMAN) and Fast Recovery Area (FRA) This article provides a comparison of storage-based snapshot technologies with RMAN and Fast Recovery Area backups. Note that since RMAN and Fast Recovery Area are built-in features of the Oracle database, this solution also applies to Oracle Exadata Database Machine, with the additional benefit of extremely high performance. Instead, customers should look to Recovery Manager (RMAN) and Fast Recovery Area (FRA) as the Oracle-supported solution to create and manage Oracle database backups. While there are benefits of using snapshots for development or testing purposes on non-production systems, they should not be considered as valid data protection or backups of Oracle databases. another storage array or tape), do not protect against media failures. This is an incorrect and dangerous assumption because snapshots, unless copied to secondary media (e.g. ![]() While storage snapshots are widely used to quickly create point-in-time virtual copies of data, they are also often marketed as valid “backup solutions”.
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