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without complex manual steps, improving the robustness of the disaster-recovery
features of Data Guard, as well as improving Data Guard manageability.
USER EXPERIENCE WITH FAST-START FAILOVER
Companies universally recognized as leaders in their industries tested Fast-Start
Failover prior to its general release. In each case, the business driver generating
interest in Fast-Start Failover is a mission critical application where high availability
is essential to the business function. For this class of applications, any outage is
unacceptable, even in the case of an event that makes an entire data-center
unavailable. In such instances the goal is a Recovery Time Objective, or the time
that it takes to have applications functioning at a remote standby site, measured in
seconds. Fast-Start Failover test participants included Amazon.com, Thomson
Legal and Regulatory, Fannie Mae, and Airbus. Quotes referencing their collective
“Fast-Start Failover takes the DBA off the
critical path. Database failover is automatic.
Data Guard can now address recovery time
objectives measured in seconds.”
—Ranjit Singh Veen,
Manager, Enterprise Systems Management
Fannie Mae
Fast-Start Failover – Oracle Data Guard 10g Release 2 Page 4
experiences are provided in this paper. A more detailed description of the
experience of Amazon.com is provided below.
Amazon.com And Data Guard Automatic Failover
At $6.92 Billion (US) in sales and over 7800 employees, it is not hard to understand
why High Availability and Business Continuity are such hot topics at Amazon.com.
Continuous availability of Amazon’s customer facing systems is essential. Any
disruption in system availability directly impacts Amazon’s bottom line.
Historically, Amazon has utilized custom-maintained standby databases to protect
business operations and data that would otherwise be impacted by system and sitewide
failures. Amazon has built-in automation through custom developed scripts
and processes that enable business continuity even in the event of complete system
or site failures. Amazon has determined that automation is critical to meeting
aggressive service level agreements.
Fast-Start Failover is designed to meet requirements such as Amazon’s. Fast-Start
Failover quickly and reliably fails over a target standby database to the primary
database role without requiring manual intervention to invoke the failover.
Continually seeking to enhance their high availability architecture, Amazon
evaluated Fast-Start Failover during early beta testing of Oracle Data Guard 10g
Release 2.
Amazon determined that Fast-Start Failover did indeed satisfy their High
Availability requirements. For the first time, an out-of-the-box solution is available
that can eliminate the overhead of supporting and maintaining custom scripts and
processes. Amazon has found that:
• Fast-Start Failover reliably executes fast, automatic failover to a standby
site without human intervention.
• Fast-Start Failover reduced failover time using Oracle Data Guard from
minutes to seconds. Average failover time was 25 seconds based on a
primary/standby pair with round-trip network latency of 0.5ms.
• Fast-Start Failover ensured zero data loss. Failover will not commence
automatically if the failover target is not synchronized with the primary
database.
• Because Fast-Start Failover is based on Data Guard Maximum Availability
protection mode, the primary production database is not impacted by
network or standby failures.
• After failover the old primary database can be automatically reinstated as a
new target standby (assuming that the database can be restarted). Data
Guard quickly and automatically resynchronizes the old primary. It no
longer needs to be restored from a backup of the new primary.
“The capability of fast, guaranteed zerodata-
loss failover with Fast-Start Failover in
Oracle Data Guard takes the availability of
an Oracle database platform to new levels.
Our initial tests running Oracle Database
10g Release 2, show that Fast-Start
Failover offers a magnitude of improvement
in availability.”
—Rajesh Sheth,
Manager, Database Engineering
Amazon.com.
Fast-Start Failover – Oracle Data Guard 10g Release 2 Page 5
The remainder of this paper provides an in-depth discussion of Fast-Start Failover,
Oracle test results, procedures for automating client failover, and Oracle
recommended best practices for configuration and operation.
CONFIGURING FAST-START FAILOVER
Fast-start Failover is used within a Data Guard configuration under the control of
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