VERITAS Volume Manager 4.1 Administrator's Guide

Chapter 11 383
11 Configuring Off-Host Processing
Introduction
Off-host processing allows you to implement the following activities:
• Data Backup—As the requirement for 24 x 7 availability becomes
essential for many businesses, organizations cannot afford the
downtime involved in backing up critical data offline. By taking a
snapshot of the data, and backing up from this snapshot,
business-critical applications can continue to run without extended
down time or impacted performance.
• Decision Support Analysis and Reporting—Because snapshots hold a
point-in-time copy of a production database, a replica of the database
can be set up using the snapshots. Operations such as decision
support analysis and business reporting do not require access to
up-to-the-minute information. This means that they can use a
database copy that is running on a host other than the primary.
When required, the database copy can quickly be synchronized with
the data in the primary database.
• Testing and Training—Development or service groups can use
snapshots as test data for new applications. Snapshot data provides
developers, system testers and QA groups with a realistic basis for
testing the robustness, integrity and performance of new
applications.
• Database Error Recovery—Logic errors caused by an administrator
or an application program can compromise the integrity of a
database. By restoring the database table files from a snapshot copy,
the database can be recovered more quickly than by full restoration
from tape or other backup media.
Off-host processing is made possible by using the FastResync and disk
group move, split and join features of VxVM. These features are
described in the following sections.
You can also use such solutions in conjunction with the cluster
functionality of VxVM.For implementation guidelines, see
“Implementing Off-Host Processing Solutions” on page 385.