9.1.20.6 New Features in Oracle Exadata Snapshots

• Hierarchical snapshot databases

  You can create space-efficient snapshot databases from a parent that is itself a snapshot. This allows for hierarchical snapshot databases. The parent snapshot is also space-efficient, all the way to the base test master. Multiple users can create their own snapshots from the same parent snapshot. The set of snapshots can be represented as a tree, where the root of the tree is the base test master. All the internal nodes in the tree are read-only databases and all the leaves in the tree are read/write databases. All Oracle Exadata features are supported on the hierarchical snapshot databases. For hierarchical snapshot databases, because there is performance penalty with every additional depth level of the snapshot, Oracle recommends having a snapshot tree with a maximum depth of 10.

• Spare Test Master databases

  You can also create and manage a sparse test master, while having active snapshots from it. This feature allows the sparse test master to sync almost continuously with Oracle Data Guard, except for small periods of time when users are creating a snapshot directly from the sparse test master. This feature utilizes the hierarchical snapshot feature described above, by creating read-only hidden parents. Note that Oracle Exadata snapshot databases are intended for test and development databases only.

• Sparse backup and recovery

  When you choose to perform a sparse backup on DB0, the operation copies data only from the delta storage space of the database and the delta space of the sparse data files. A sparse backup can be either in the backup set format (default) or the image copy format. RMAN restores sparse data files from sparse backups and then recovers them from archive and redo logs. You can perform a complete or a point-in-time recovery on sparse data files. Sparse backups help in efficiently managing storage space and facilitate faster backup and recovery.

  See Oracle Database Backup and Recovery User’s Guide for information about sparse backups.

Minimum hardware: Storage servers must be X3 or later

Minimum software: Oracle Database and Grid Infrastructure 12c release 2 (12.2), and Oracle Exadata Storage Server software release 12.2.1.1.0.