Data Recovery for Informix (SAP Library - SAP Database Guide: Informix (BC-DB-INF-DBA))

Data Recovery for Informix

Purpose

Data recovery is the set of measures that enable your Informix database to be restored to a consistent state following a failure in which data is lost or damaged (for example, due to a fire).

Informix provides the tools ontape , ON-Archive , and ON-Bar for data recovery.

Note

This section refers to "backups" in the general sense of any copy of database data taken for the purpose of data recovery. In this general sense, the term includes archives, which is the term used for the tools ontape and ON-Archive .

Implementation Considerations

It is extremely important to implement data recovery for your Informix database running with the SAP System. SAP strongly recommends you make sure that you can recover data in the event of failure.

Caution

If you do not take routine backups of the database during normal production, you risk losing data.

You must choose one of the Informix data recovery tools – that is, ontape , ON-Archive , and ON-Bar – and stick to it. This is because backups taken with different tools are not compatible.

To make sure that you can use data backed up for restore, SAP recommends that you:

Develop a well thought-out approach to data recovery

Keep a sufficient number of backup tapes and store at least some offsite

Test your backup and restore procedures from time to time, especially after major system changes

Integration

SAP does not provide tools for data recovery, but instead integrates some of the Informix tools into the SAP System and SAPDBA:

The Computing Center Management System (CCMS) of the SAP System integrates ON-Archive , and it is planned to integrate ON-Bar in the future. You can schedule backups in the Database Planning Calendar of CCMS, and check the results afterwards.

SAP scripts help you set up ON-Archive .

Recovery Report with SAPDBA can be produced to minimize the time for a restore using ON-Archive .

Features

The essential features of data recovery are as follows:

Making frequent regular backups of the database during normal production (that is, before a failure has occurred). Note that backups do not affect normal production.

Restoring the database to a consistent state following a failure, using backups of the database previously taken during normal production.

Constraints

You can only perform data recovery using the authorized Informix tools ontape, ON-Archive , or ON-Bar .

Caution

You can not use Informix data-migration tools such as onunload or dbexport for data recovery, because these tools are not coordinated with the information stored in the logical-log files, and they do not store the necessary system-overhead information required for data recovery.