Guidelines for Archive (ON-Archive and ontape) 

The following guidelines apply to Informix database archive with ON-Archive or ontape :

You can archive while the Informix database server is fully online and no extra risk is involved. Data consistency is maintained, which means that you can restore the database correctly (to the point the archive was started) without using logical-log files, unlike most other database systems. The exception to this is parallel archives, which require the logical-log files to be present if a restore is later necessary. Always follow a parallel archive with a logical-log file backup.

You can archive in quiescent mode, but this is normally unnecessary. You cannot archive in offline mode. For more information about Informix database server modes, see Server Mode with SAPDBA and the Informix documentation.

An archive, particularly one that uses software compression, may affect the performance of the Informix database server. Since performance of your database is critical, you should do your archives during off-peak hours.

Sometimes, you should perform a full (level-0) archive in sequential mode. The Informix documentation provides information about database administration activities requiring such full archives.

For example, you have to perform a full database archive after changing the configuration of the physical and logical logs. Full archives are also required with Reorganize Single Table, Reorganize Group of Tables and Reorganize Dbspace in SAPDBA. You are also strongly advised to do a full archive after performing an emergency backup of the logical log. Refer to Emergency Logical-Log Backup. For a summary of measures you can take to avoid the problem of emergency logical-log backups, see Preventing Emergency Logical-Log Backup.