Start of Content Area

Procedure documentation Choosing Archive Levels and Frequency (ON-Archive and ontape)  Locate the document in its SAP Library structure

Use

There are the following database archive levels for ON-Archive and ontape available with the Informix database:

Level

Description

0 (full)

Archives all used pages. The most secure but biggest and longest archive

1

Archives all changes since the last level-0 archive

2

Archives all changes since the last level-1 archive

Archives at levels 1 or 2 are known as "incremental".

Caution

Be very careful when using level-1 or level-2 archives because they depend on the previous level-0 archive. If the last level-0 archive is lost or unreadable, existing level-1 or level-2 archives are useless if the database needs to be restored. For more information about how to check that your data is readable for a restore, see Data Consistency with SAPDBA.

Procedure

  1. If possible, perform a level-0 database archive every day. In the event of failure involving data loss, you can restore your last level-0 archive and then apply the logs backed up during the day of failure.
  2. Have enough tape drive capacity to perform unattended full database archives. If this is possible, it becomes much easier to perform frequent full (level-0) database archives with large databases, since you do not need to continually mount new tapes.
  3. Only perform full (level-0) archives unless the database is so large that incremental (level-1 and level-2) archives are really necessary. Remember that an incremental archive is no use on its own. It can only be used with an earlier full archive.

Result

You have decided on the level and frequency of archive. This is an essential part of your archive approach. Therefore, you can be more sure that, in the event of failure involving data loss, you have a suitable archive that you can use to quickly restore the database with minimal data loss.