Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

Understanding
point-in-time copy methods
This chapter includes the following topics:
■ About point-in-time copies
■ About point-in-time copy technology
■ Point-in-time copy use cases
About point-in-time copies
Two trends dominate the evolution of digital data used to conduct and manage
business. First, more and more data must be continuously available for 24x7
transaction processing, decision making, intellectual property creation, and so
forth. Second, as digital data assumes a larger role in the conduct of business,
protecting it from loss or destruction becomes increasingly important. These
trends run counter to each other. To protect it properly, data must be taken out
of service so that it stands still while it is backed up. But taking data out of service
means that it’s not there when the business needs it. To solve this problem,
information technology has developed a set of techniques for freezing
instantaneous images of data—for taking snapshots of it—that can be used to make
backups, perform analyses, and test software updates, all while production
applications continue to operate on the live data.
Point-in-time copies of volumes allow you to capture an image of a database or
file system at a selected instant for use in applications such as backups, decision
support, reporting, and development testing.
Point-in-time copy solutions may additionally be configured to use off-host
processing to remove much of the performance overhead on a production system.
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