Plus, the best practices for backup and restore are easy to grasp and straightforward
to implement.
But there is a catch. It takes time to restore a database after a failure or corruption. The
restore process could last for hours, while end-users sit idle. Hence, with a backup and
restore strategy, there is considerable latency, as well as latency in the sense of a delta between
the content of the backup and the primary database at the moment of failure (Disaster
Rada deh & Al-Ameed
Copyright ?© 2007, Idea Group Inc. Copying or distributing in print or electronic forms without written permission
of Idea Group Inc. is prohibited.
Recovery Package, 2004). The latency of backup and restore can be reduced considerably
by implementing a so-called cold standby which simply extends the backup process by an
extra step that restores backups to a standby database server. Since the standby database is
cold, it takes a few minutes to bring it online, but this is a fraction of the latency of a restore
process. If the scenario periodically sends transaction logs from the primary to the standby,
it will serve to reduce the latency of database content. Hence, a cold standby extends triedand-
true backup-and-restore procedures to achieve database high availability with a level
of data loss that is acceptable for lower-valued transactions.
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