Data Services is a key offering within Oracle’s Maximum Availability
Architecture. It’s really a must-have for organizations that are using Oracle
high availability technologies such as Active Data Guard or Oracle GoldenGate
to replicate data across multiple databases. With automated workload balancing
and service failover capabilities, GDS improves performance, availability,
scalability, and manageability for all databases that are replicated within a
data center and across the globe. And GDS boosts resource utilization, which
really improves the ROI of Active Data Guard and GoldenGate investments. It
does this in an integrated, automated way that no other technology can match.
Plus it’s included with the Active Data Guard license - and since GoldenGate
customers have the right to use Active Data Guard, it’s available to them at no
additional charge as well.
typically deploy replication technologies for various business requirements –
high availability and disaster recovery, content localization and caching,
scalability, performance optimization for local clients or for compliance in
accordance with local laws. Oracle customers
use Active Data Guard and Oracle GoldenGate to address all of these business
requirements. They use Active Data Guard to distribute their Read-Only workload
and GoldenGate to distribute not only Read workloads but also Read Write
workloads across their replicated databases.
when you’re trying to optimize workload management across multiple database
replicas, you run into certain challenges that simply extend beyond the
capabilities of replication technology. That’s because customers are unable to
manage replicated databases with a unified framework and instead have to deal
with database silos from an application and DBA perspective.
Let’s look at a couple of the
main problems with database silos.
- The first is under-utilized resources – for example, when one
replica cannot be leveraged to shoulder the workload of another over-utilized
database. This leads to suboptimal resource utilization, which can adversely
affect performance, availability and of course cost.
- The other problem with silos is the inability to automatically fail
over a service across databases - let’s say a production application workload
is running against a particular replica. If that replica goes down due to an
unplanned event, customers don’t have a mechanism that automatically and
transparently relocates the Service to another available replica. When a
replica fails that can lead to application outages.
the introduction of Oracle Global Data Services (GDS), there really wasn’t a
way for enterprises to achieve Service Failover and load balancing across
replicas out of the Oracle Stack. To address this, some customers have chosen
to compile their own homegrown connection managers and others have integrated
their HA stack with hardware load balancers. But these solutions still don’t
address all of the issues:
- Manual load balancing using
homegrown connection managers, for example, incurs huge development costs and
yet cannot optimize performance and availability for replicated systems
- Special purpose network load
balancers can help but they introduce additional cost and complexity – and they
still can’t offer database service failover and centralized workload management
Global Data Services Overview
Data Services delivers automated workload management, which addresses all of
these key pain points. It eliminates the
need for custom connection managers and load balancers for database workloads.
newly created concept called Global Service,
Oracle Global Data Services extends the familiar Oracle RAC-style connect-time
and run-time load balancing, service failover and management capabilities
beyond a single clustered database. Capabilities that were so far applicable
only to a single database can now be applied to a set of replicated databases
that may reside within or across datacenters. Customers can achieve these
capabilities by simply setting the pertinent attributes of the Global Service.
GDS sits between the application tier and the
database tiers of the stack. It orchestrates the Service high availability,
Service level load balancing and routing. Global Services run on the databases
but are managed by GDS. GDS algorithms take into account DB instance load, network
latency between data centers and the workload management policies (region
affinity, load balancing goals, DB cardinality, DB role, replication lag
tolerance) that the customers can configure. These workload management policies
are enabled via the attributes of a given Global Service.
What are the key capabilities that are really unique to GDS?
performance optimization, there’s region-based workload routing, which
automatically routes workloads to the database closest to the clients. For
example, what if the customer has a requirement that all the
clients/applications closer to the North American data center need to be routed
to the database in the North American data center? Likewise, European clients
may need to be routed to the European database. GDS addresses this problem by
managing this workload routing automatically.
addition, GDS provides connect time load balancing and supports run time load
balancing – another key performance advantage.
higher application availability, GDS enables inter-database service failover.
If a replica goes down as a result of a planned or unplanned event, GDS fails
over the service to another replica
4. And it
also offers role based global services. GDS will make sure that the global services
are always started on those databases whose database role matches the role
specified for the service. For example, if Data Guard undergoes role
transitions, the global services are relocated accordingly, maintaining
5. For improved
data quality, there’s also replication lag-based workload routing. This
capability routes read workloads to a Data Guard standby whose replication lag
is within a customer-specified threshold that’s based on business needs
managing all of the resources of the replicas efficiently, customers are able
to maximize their ROI because there are no longer any under-utilized servers
wraps up the introductory blog post on Oracle Database 12c GDS. We looked at the challenges of workload
management for replicated databases and how GDS addresses those challenges. In
the next blog, we will review some of the key capabilities of GDS and the
tangible business benefits.