Real-time, heterogeneous, and transactional data replication
capabilities make Oracle GoldenGate a key component of the Oracle
Database Maximum Availability Architecture.
Listen to this recently recorded podcast to
hear Nick Wagner from Oracle GoldenGate product management team, and Joe
Meeks from Oracle Database product management team discuss how to use
GoldenGate for maximum availability and the new features of GoldenGate
11gR2 that strengthen its high availability solutions.
This podcast is a little recap of the great live webcast we hosted back in December 2012. In case you missed it, make sure to watch it on demand, at your convenience.
Great questions were asked during that webcast, and our expert Joe Meeks was able to answer plenty of them. Here are some great examples of that:
Q: What is the difference between the logical standby and GoldenGate ?
Joe: Data Guard logical standby (SQL Apply) is an included feature of Oracle
Enterprise Edition. It utilizes all of the same transport and role
management features used by Data Guard Redo Apply (physical standby
database), but it uses SQL to apply changes to a standby database that
is open read-write (physical standby uses media recovery). The focus
SQL Apply is as a feature of Data Guard for database rolling upgrades.
The process begins with a primary and Data Guard physical standby. The
standby is converted to a logical and upgraded. Production is then
switched to the standby and the original primary (now a standby) is
upgraded. From 11g onward we use the Transient Logical Rolling Upgrade
Process - this results in the upgrade concluding with a primary and
physical standby both at the new version. SQL Apply is only used for
replication across version
GoldenGate is our comprehensive
logical replication product. It is meant to address all advance
replication needs and is the preferred solution for requirements such as
reporting offload where the target database must be open read-write,
bi-directional and multi-master replication, zero downtime
upgrades/migrations, data integration, etc.
Q: What is it that Oracle Data Guard can do that Oracle GoldenGate can't ?
Joe: This is a backward way of asking this question . GoldenGate is a
comprehensive, feature rich replication product. It can do many things
Oracle Data Guard can't.
Data Guard is very focused - simple
physical replication. Unlike GoldenGate, it maintains an exact physical
replica of the primary (backups are interchangeable), it has no
datatype or other restrictions to consider, it uses standard Oracle
Media Recovery so has very high performance for all workkloads, it has
advanced corruption protection - lost-write protection and automatic
block repair. It offers both Synchronous (a guarantee of zero data
loss) and Asynchronous replication.
Data Guard's primary goal is to provide the simplest, fastest, most complete data protection for Oracle Database, period.
primary goal is to provide the most feature-rich replication solution
for the broadest possible range of requirements.
My recommendation is to first understand your requirements and preferences, then chose the right tool for that job.
Q: How can we use the new DBFS in conjunction with Oracle Data Guard and GoldenGate ?
Joe: DBFS is useful in a GoldenGate configuration to store the GoldenGate
trail files and checkpoint files in DBFS to provide recoverability and
failover capabilities in the event of a system failure. Using DBFS is
fundamental to the continuing availability of the checkpoint and trail
files in the event of a node failure. Ensuring the availability of the
checkpoint files is essential to ensure that, after a failure occurs,
the Extract process can continue mining from the last known archived
redo log file position and Replicat processes can start applying from
the same trail file position before a failure occurred. Using DBFS
allows one of the surviving database instances to be the source of an
Extract process or destination for the Replicat processes.
Data Guard perspective - anything that is in DBFS is protected just as
any other database data is protected. So DBFS provides a way to have
Data Guard protect file system content for you as well that would
otherwise be external to the Oracle database.