Data Consistency, Recovery, and Migration 4-5
In This Chapter
Several OnLine tasks that are critical to long-term operation are performed
automatically.As administrator, you might find it interesting and helpful to
understand what these tasks are and why they are important.
Consistency-checking code has been implemented throughout the OnLine
productto help alert administrators to occurrences of data inconsistency.The
function of the code is, at minimum, to write messages to the OnLine
messagelog if inconsistencies are detected. Administrators can also ask users
toset consistency-checking environment variables that will direct OnLine to
generate diagnostic output if inconsistencies are detected.
SeveralOnLine features provide for data recovery.This chapter explains how
eachfeature works, both independently and with other features, to preserve
and restore data in the event of operating system or media failure.
This chapter compares four migration methods to help you select the best
migration method for the task. Following the comparison of the migration
methods, each method is explained step-by-step.