Tuesday Tips: High Availability in a Blackout


The summer season is upon us. While Memorial Day triggers excitement for vacations, hot days lounging by the pool and warm nights spent around the BBQ, ever present is the increased concern for city-wide or regional brownouts or blackouts as power sources are drained.
Let’s not forget the major black out of 2003, which resulted in major outages across the North East and plunged NYC into darkness. For IT professionals and database administrators, the impact of a power outage is far reaching. Countless business applications run on databases, specifically Oracle databases. A downed application could cost companies significantly, so the responsibility falls on the DBA to make sure the underlying database has high availability.
Frank Franklin II/Associated PressAppeared on The New York Times


Oracle database high availability can be affected by planned and unplanned system outages. Today we’ll share two tips on ways to reduce impact of unplanned system outages:

  • Think through your disaster recovery strategy: If you have an Oracle database in place, chances are you are already using built-in recovery functionality. The functionality fails over to another server, but does not protect against permanent storage failures and the range between servers is limited. Many companies deploy third party disaster recovery solutions (hardware and software) that protects data over a LAN. In the case of a regional power outage, the probability is high that two servers are within close proximity of one another and are both impacted.

We’re in BIG trouble if a power outage spans a continent. Since that scenario is unlikely, a data replication solution that replicates to servers in different regions provides a better approach.

TIP: Consider a high-performance data replication solution that replicates data asynchronously. Dell offers SharePlex, which only replicates application changes to the database – called Change Data Capture. The bandwidth requirements are less and there are no limitations on physical distance between the source server and the target server.

  •  Plan to minimize impact from high system loads: While we may be entering a summer slowdown, the speed at which data is coming into an organization is anything but slow. Real-time information is critical to business analysts and executives. Again, for the DBA, this means your Oracle database must be available to handle intake while also being available for reporting and analytics purposes.

 TIP: To avoid unplanned outage or lag due to a planned reporting need, consider a solution that creates a secondary instance of transactional data. SharePlex can replicate data to offload reporting from the production environment, easing the strain.


While DBAs can’t predict for a brownout, blackout or other disastrous scenario this summer, they certainly can plan for the worst. Learn how in our complimentary white paper, “Ensuring High Availability for Critical Systems and Applications.” You’ll discover how to deliver on availability SLAs through planned and unplanned outages.