It's clear that the public cloud and the private cloud are two important future trends that are looming over IT. For cloud-based database services, Microsoft has implemented SQL Server in the public cloud with SQL Azure. Most businesses are very hesitant to jump into the public cloud for multiple reasons, including concerns about security, ownership of data, performance, accessibility, and legal boundaries for where data resides.
However, the private cloud is another story. The private cloud offers most of the same benefits as the public cloud, and because it's implemented using your organization's resources, IT remains in complete control of its infrastructure. In addition, the private cloud provides similar flexibility and to some degree similar scalability benefits as the public cloud. Although the private cloud might offer fewer overall computing resources than a Microsoft global data center, it can be designed to offer computing power that matches the organization's demands. More importantly, the private cloud enables resources, such as virtual machines (VMs), to be moved dynamically between hosts in response to changing workloads. For Microsoft infrastructures, Microsoft System Center Virtual Machine Manager 2012 (VMM) will be the platform that enables the private cloud.
However, does SQL Server really fit into the private cloud? A SQL Server database isn't like a web server where you can add servers to a web farm and immediately gain scalability benefits. SQL Server clusters are designed to increase availability, but they aren’t designed to increase scalability. Sure, you can utilize features such as distributed partitioned views to create scale-out databases. However, this requires you to re-architect your database, and the process isn’t nearly as simple as adding a new server to a cluster. Furthermore, applications are designed to connect to a specific database that's hosted by a particular SQL Server instance. Although future versions might change the way databases are implemented, at this point databases don't really move between servers. In many ways, SQL Server and enterprise databases seem like they would be poor candidates for the private cloud. For the most part, databases are fixed entities and aren't very dynamic.
Although there are limitations, SQL Server can definitely participate in the private cloud. With that said, a critical prerequisite for taking advantage of the private cloud is virtualization. This technology is the key enabler for dynamic automated management. Although databases themselves don't move between servers, technologies such as live migration coupled with VMM 2012's Dynamic Optimization lets you move VMs dynamically between hosts in response to changing CPU and memory demands. This lets you move virtualized SQL Server instances to new hosts in case the CPU or memory utilization in the VM or its host exceeds a given level. This can help your applications to continuously meet service level agreements (SLAs) without requiring manual intervention.
With System Center 2012, it's also possible to take advantage of the automated management technologies in Orchestrator to create runbooks that dynamically reconfigure VMs to hot-add CPU or RAM. In addition, a new generation of database hardware, such as the HP Database Consolidation Appliance (DBC), let you essentially create a private cloud for all of your on-premises databases. To learn more about the DBC Appliance, see "First Look: HP Enterprise Database Consolidation Appliance" and Hewlett Packard's product page.
The private cloud also helps with the deployment of new applications. The private cloud provides a higher level of management in which IT can work with applications as services, rather than working with individual VMs that might be required to deploy the application. The service is a collection of VMs and other virtual resources that perform a common task. For instance, a service might consist of two VMs that act as front-end web servers, another VM that provides middle-tier application logic, and a fourth VM that provides SQL Server database services. The private cloud lets all related VMs be deployed as a single unit or service. They can also be turned on or off and managed as a single unit. Finally, features such as Dynamic Power Optimization in VMM 2012 can take advantage of private cloud resources to reduce power consumption during periods of low resource utilization.
The private cloud will definitely be a growing trend throughout the next couple of years, and SQL Server isn’t excluded from playing in the cloud. You don't need to move to technologies such as the public cloud and SQL Azure to gain flexibility, scalability, and dynamic operations. You can have all the same benefits with the private cloud by using the resources your organization already has.