Protecting Your Data : After-imaging : After-image sequences
After-image sequences
The SEQUENCE qualifier to the RFUTIL utility provides database administrators the ability to update after-image sequence numbers and improves your ability to maintain a hot standby database recovery strategy.
RFUTIL SEQUENCE updates the sequence number of your hot standby target database to match the sequence number of the AI extent that was BUSY at the time the source database was copied to create the hot standby.
After executing RFUTIL SEQUENCE on your standby target database, you can keep the target in sync with the source by rolling forward AI extents, starting with the extent that was BUSY when the copy occurred.
A hot standby is typically maintained by first making a copy of your source database, and then regularly updating the database by rolling forward the AI extents from the source to the target. The preferred methods of making a copy of your database use the OpenEdge utilities PROCOPY or PROBKUP. However, if you use your operating system commands to make a copy, the SEQUENCE qualifier to RFUTIL is available to update your target database to expect the correct after-image extent in the roll forward sequence. Correcting the sequence is only necessary if there has been an AI extent switch on your source database after the database was last marked as backed up and before the operating system copy was made.
