HA and DR Protection
The following slides highlight three ways you can provide high availability and disaster recovery protection for SQL Server in the cloud.
Use Windows Server Failover Clustering in the Cloud
Because SQL Server is a business-critical application, you need to provide high-availability protection for it, regardless of where it is deployed. In the cloud, you need to protect SQL from downtime if the cloud instance or the cloud provider fails. While most cloud providers offer multiple availability zones — generally separate and redundant data centers or computing resources — they do not offer shared storage (i.e., a SAN), which is required to support traditional Windows Server Failover Clustering (WSFC) across cloud-availability zones.
You can use SANless software instead of a SAN to create a high-availability cluster using WSFC. You can configure redundant SQL Server application instances in different cloud availability zones. When a failure occurs, WSFC will coordinate SQL application restart to the second environment in a different availability zone.
Ensuring an Always-Available SQL Server Cloud Deployment
Ensuring an Always-Available SQL Server Cloud Deployment
Companies are moving more business operations to cloud and hybrid cloud configurations. Others are adding cloud failover instances to their physical server environments for disaster recovery without the cost of building out a disaster recovery site. Yet, misperceptions and concerns about high availability and disaster protection have made decision making difficult for companies moving their mission-critical applications (i.e., SQL Server, Oracle, and SAP) to the cloud, where traditional shared-storage clusters are impractical or impossible. To fully leverage the benefits of cloud and hybrid cloud environments, companies need to separate myths from facts and consider a new approach to HA and DR.
In this slideshow, Jerry Melnick, president and CEO of SIOS Technology, takes a closer look at five common misconceptions surrounding high availability in the cloud and how SANless clusters can help overcome some of the obstacles.
- Public cloud deployments are automatically high-availability environments where application downtime is negligible. This is not true. Clouds are not high-availability environments unless you add HA protection.
- You cannot protect business-critical applications in a public or private cloud by using a cluster. The truth is, HA is a physical deployment with a failover cluster using shared storage (SAN). Public clouds (e.g., Amazon EC2, Azure) have no concept of a cluster-aware shared storage.
- Applications and data are protected from disasters in the cloud without additional configuration. The reality is that cloud providers experience downtime and regional disasters like any other organization.
- You can either run your application in the cloud or in your on-premise data center, but not both. In truth, you can have both. You can use your on-premise data center as your primary site and the cloud as your hot standby DR site. On-premise servers can be SAN-based or SANless clusters or a single server not participating in a cluster.
- Creating an HA environment in a cloud requires complex scripting, specialized skills or added complexity. The opposite is actually true. HA cluster in a cloud is very easy without adding another SAN with SANless clusters.
