Question: What is Oracle n-way
Streams replication? I hear that n-way Streams replication is a faster
failover alternative to Data Guard, but I see nothing in the Oracle
documentation on n-way Streams. How does n-way Streams replication
work?
Answer: You are correct, you
will not find n-way Streams mentioned in the Oracle documentation because it
is a specialized techniques that combines high availability with disaster
recovery, all without the expense of RAC clusters.
N-way streams can also serve as a low-cost alternative
to RAC, in low-DML systems.
Some shops will place RAC nodes in separate buildings in
the same neighborhood, but with the advent of the superfast dark fiber
interconnect (Dense Wavelength Division
Multiplexing (DWDM) technology), you can use “Extended
RAC” and place RAC nodes up to 100 miles apart.
However, dark fiber is super-expensive, and most shops adopt a best
practice where they combine RAC with disaster recovery solutions like n-way
Streams replication.
With n-way Streams, geographically separate instances cross-feed each
other using Streams replication. Using this technique you can have
high availability combined with disaster recovery and use automatic failover
to redirect end-users if a single server in the Streams cluster fails.
