In this article, we look at how we can get AlwaysOn features in SQL Server to work with Amazon AWS
Many organizations using SQL Server, make use of cloud services for not only storing active data but also backups. The most preferred options of cloud storage by such organizations are Azure Cloud and Amazon Web Services (AWS). Although, Azure cloud is specifically tailored for SQL Server users, and is a product of Microsoft, AWS has no such specifications. Still, both of these cloud storage platforms are equally reliable and provide users with multiple options, AWS also allows users to make use of high availability features, while using the platform. The AlwaysOn Availability Groups can be used along with AWS for creating an asynchronous replica of your database in the cloud storage platform.
What can be done with Availability Groups in AWS
Although AGs are already a very useful feature, you can make us of all AlwaysOn Availability Groups’ functions by creating another AG. You can not only get the Availability Groups Listener too begin working, but also configure readable replicas with a few more steps. An Availability Group Listener is that part of an AG which is used for sending requests to any readable secondary. If you do not make use of the listeners, it will be up to you and your networking team to somehow create and maintain load balancers, along with taking up responsibility for sending correct writes to SQL Server.
Incompatibilities that may Arise while using AGs with AWS
The feature of High Availability is in-built in SQL Server, whereas AWS is a non – SQL cloud service. Although AWS is compatible with SQL databases, there are still some incompatibilities which arise while using both. The greatest issue is that the Automatic Failover will not work, it is not supported by Amazon network stack. Using Synchronous commit with Automatic failover in AlwaysOn Availability Groups is necessary to fight additional latency.
How will AGs in AWS Benefit Users
For organizations planning to switch to cloud, this move comes as a great benefit or advantage. Although you will not be able to use all the features of AlwaysOn Availability Groups, getting to use a few of them is also wonderful. The existing SQL licenses can be used by organizations for developing an AG, to easily have access to multiple disaster recovery sites. Due to recent cloud outages, organizations have become aware of the vulnerabilities of redundancy, with AG you can now deploy a strategy to survive outages.
Key Points to Remember
The AlwaysOn Availability feature in SQL Server is available in Enterprise editions only.
For deploying AlwaysOn in AWS, you will need SQL licenses, thus restricting you from making use of Amazon’s SQL Server images. For automatically deploying SQL in AWS, you will be needing someone with great expertise, not just a DBA. This will require lot of effort and patience, but will certainly be worth it. Also as a backup measure always keep a recover mdf tool around to deal with any contingencies.
Victor Simon is a data recovery expert in DataNumen, Inc., which is the world leader in data recovery technologies, including corrupt access and sql recovery software products. For more information visit www.datanumen.com