Database Reference
In-Depth Information
Chapter 7
SLA-Driven Database Replication
on Virtualized Database Servers
One of the main advantages of the cloud computing paradigm is that it simplifies the
time-consuming processes of hardware provisioning, hardware purchasing and soft-
ware deployment. Currently, the increasing numbers of cloud-hosted applications
are generating and consuming increasing volumes of data at an unprecedented scale.
Cloud-hosted database systems, such as virtualized database servers, powering these
applications form a critical component in the software stack of these applications.
Service level agreements (SLAs) represent the contract which captures the agreed
upon guarantees between a service provider and its customers. The specifications of
existing SLA for cloud services are not designed to flexibly handle even relatively
straightforward performance and technical requirements of customer applications.
In this chapter, the problem of adaptive customer-centric management for
replicated virtualized database servers in single or multiple data centers is tackled.
A novel adaptive approach for SLA-based management of virtualized database
servers from the customer perspective is presented. The framework is database
platform-agnostic, supports virtualized database servers, and requires zero source
code changes of the cloud-hosted software applications. It facilitates dynamic
provisioning of the database tier in software stacks based on application-defined
policies for satisfying their own SLA performance requirements, avoiding the cost
of any SLA violation and controlling the monetary cost of the allocated computing
resources. In this framework, the SLA of the customer applications are declaratively
defined in terms of goals which are subjected to a number of constraints that are
specific to the application requirements. The framework continuously monitors
the application-defined SLA and automatically triggers the execution of necessary
corrective actions, such as scaling out the database tier, when required. Therefore,
the framework is able to keep several virtualized database replica servers in different
data centers to support the different availability, scalability and performance
improvement goals. The experimental results demonstrate the effectiveness of the
SLA-based framework in providing the customer applications with the required
flexibility for achieving their SLA requirements.
