Over the course of the past few articles I’ve been covering some of the issues around moving your databases to the cloud. While the cloud is rapidly becoming an integral part of many IT infrastructures businesses have been reluctant to move their database workloads from on-premise into the cloud – and rightfully so. The primary concern centers around the ability to remain in control of your data. When that data is on-premise you are in control of it. When that data is in the cloud that control is in the hands of the cloud provider. There are other concerns as well. The ability for multitenant cloud hosts to provide adequate performance is an important concern. Security is another big issue and for some countries there is the need to ensure that all of their data is maintained within that country’s geographical boundaries. These sort if issues make moving to the cloud difficult and in some cases impossible. However, the cloud doesn’t have to be an all or nothing affair. The hybrid cloud provides a middle-of-the-road solution that can enable you to leverage cloud technologies where they make sense yet still maintain control of and security over your on-premise databases.
With the hybrid cloud you can utilize your on-premise infrastructure for your day-to-day operations but also take advantage of the cloud for other related operations like backup, high, availability or disaster recovery, For instance, one of the scenarios that utilize the hybrid cloud can be seen in SQL Server’s AlwaysOn Availability Groups. AlwaysOn Availability Groups were first introduced with SQL Server 2012. However, SQL Server 2014 adds several enhancements that enable you to take advantage of the hybrid cloud. AlwaysOn Availability Groups enable you to replicate the changes in multiple related databases to one or more secondary replicas. These secondary replicas can be on-premise and used for high availability or in the case of the hybrid cloud the secondary replicas could be located in the cloud and used for disaster recovery, reporting or backups. On-premise replicas typically use synchronous replication and can provide automatic failover. Secondary replicas in the cloud typically use asynchronous replication and they require manual failover for disaster recovery scenarios. SQL Server 2014 provides built-in Azure integration that enables this kind of hybrid cloud scenario. Likewise, SQL Server 2014 also has the ability to backup to Azure enabling you to easily leverage the cloud for offsite storage. The key to making hybrid cloud scenarios work is the network link between your on-premise network and the network that’s provided by the cloud provider. Typically you need to have a hardware or software VPN in place that bridges your local network and the cloud. The VPN is responsible for securely routing your local network traffic to the cloud.
The cloud doesn’t need to be an all or nothing solution. The hybrid cloud can be an effective way to leverage cloud technologies while still maintaining your primary database workloads on-premise.