About snapshot modes supported by Storage Foundation for Databases (SFDB) tools
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About snapshot modes supported by Storage Foundation for Databases (SFDB) tools

The following are the snapshot modes supported by SFDB tools:

Review the following information about the supported snapshot modes.

Table: Description of Snapshot Modes describes the two snapshot modes.

Table: Description of Snapshot Modes

Snapshot mode

Description

Online

The online snapshot mode:

  • Is like an online or a hot backup of the application or the database and it is suitable as a backup image.

  • Requires the application to support online or hot backup mode. The Oracle database is put in the hot backup mode until the snapshot is taken.

  • Requires the database to be open.

  • Requires the database to be in the archivelog mode.

    Note:

    Most production databases are in the archivelog mode.

  • Has the least performance impact on the application or the database.

  • Allows restore of the primary application data from the snapshot image.

  • Allows the user to perform manual point-in-time recovery of a clone based on the snapshot or of the primary application after a restore operation.

Instant

The instant snapshot mode:

  • Is like a crash-consistent image of the application or the database and is not suitable as a backup image.

  • Freezes the application I/O so that a crash-consistent snapshot can be taken. Application I/O is frozen by freezing all the file systems holding the application files or data. Application I/O is frozen for the duration of the snapshot process.

  • Does not require the database to be in the archivelog mode.

  • Has some performance impact on the application or the database, since application I/O is frozen while the snapshot is being taken. However, the snapshot process itself may be faster, especially under heavy transactional load on the database.

  • Is not supported for standby databases.

  • Is supported on Oracle 12c, Oracle 10g Release 2 patch level 5, or on the Oracle 11g series.

  • Is supported on Oracle 10g Release 2 patch level 5, or on the Oracle 11g series.

  • Is supported for RAC databses.

Offline

The offline snapshot mode:

  • Is like a cold backup of the application or the database and it is suitable as a backup image.

  • Requires the application to be offline.

  • Requires the snapshot configuration to be validated when the application is online.

  • Is fastest amongst the snapshot modes.

  • Does not require the database to be in the archivelog mode.

  • Requires that database instance(s) should not be running, in case of Oracle.
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