This is the second of two newsletters that is focused on the impact that cloud computing is having on application delivery. With that objective in mind, this newsletter will look at the pros and cons of cloud balancing.
Cloud balancing refers to routing service requests across multiple data centers based on myriad criteria. Since cloud balancing involves one or more corporate data centers and one or more public cloud data centers, cloud balancing is an example of hybrid cloud computing.
Cloud balancing can be thought of as the logical extension of global server load balancing (GSLB). The goal of a GSLB solution is to support high availability and maximum performance and as a result, a GSLB solution typically makes routing decisions based on criteria such as the application response time or the total capacity of the data center. A cloud balancing solution may well make routing decisions in part based on the same criteria as used by a GSLB solution. However, a cloud balancing solution extends the focus of a GSLB solution to a solution with more of a business focus and so would make routing decisions using a variety of criteria including the cost to execute a transaction at a particular cloud.
In addition to potentially lowering cost, cloud balancing can potentially improve performance by directing a service request to a data center that is close to the user and/or one that is exhibiting the best performance. Cloud balancing also helps to reduce risk because hosting applications and/or data in multiple clouds increases the availability of both. Balancing can be performed across a number of different providers or it can be performed across multiple independent locations of a single cloud service provider. In view of the Cedexis data that was mentioned in the last newsletter, cloud balancing across two or more independent Infrastructure as a Service (IaaS) solutions may be required in order to achieve acceptable availability.
However, in order to achieve the benefits of cloud balancing the collection of individual data centers must appear to both users and administrators as a single cloud data center, with the physical location of application resources as transparent as possible. This has a number of implications. One implication is that it is very beneficial if there is a consistent architecture across the private and public clouds. It is notably easier to have a consistent architecture across a cloud balancing solution if the GSLB function is provided by a virtual ADC (vADC). Other implications include the need for optimizing application performance and providing interoperability between the local and the global ADC functions.
Much more information on the impact of cloud computing on application delivery can be found here.