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Procedure documentation Using Parallel Archive (ON-Archive)  Locate the document in its SAP Library structure

Use

ON-Archive allows you to group one or more dbspaces in the Informix database into dbspace sets, which can be simultaneously archived to different volume sets independently of each other, that is, "in parallel". The advantage of performing parallel database archives is that they are more rapid than sequential archives. Therefore, parallel archives are useful for very large databases.

Caution

You must always create a logical-log backup after a parallel archive to make sure that you can restore the database in the event of a failure. Unlike a sequential archive, a parallel archive cannot be used for a restore without the accompanying logical-log files, so a logical-log backup is essential.

Procedure

  1. Decide whether to use parallel archives.

    2. If possible, you should archive sequentially. Assign several physical tape drives to one logical device if you have so much data that it exceeds one tape volume. Then you can perform the archive overnight in unattended mode. The archive is written in sequence to a number of tapes mounted on a series of tape drives.

    Caution

    ON-Archive does not provide a tool to check whether the total dbspace sets of a parallel archive correspond to the data volume of the entire database. For example, ON-Archive does not check whether you have forgotten to archive a specific dbspace. If the database needed to be restored, you could not restore a missing dbspace. In general, take extra care with parallel archives.

  2. Decide whether to use the DBA Planning Calendar in the Computing Center Management System (CCMS) of the SAP System for parallel archives.

The DBA Planning Calendar automatically groups the dbspaces of your database into dbspace sets to enable parallel archives. For more information about setting up your dbspace sets independently – not recommended by SAP unless necessary – see the Informix documentation.

Caution

Although it is possible to do a partial archive of your database (that is, only archive certain dbspaces, but not all), SAP strongly advises against this. The SAP System is so integrated that it makes little sense to archive only one section of the database.