Windows 2012R2 Failover Cluster With SQL Server 2014 AlwaysOn Options #part1 #cloud #azure #winserv #SQL #msteched

With the new version of SQL server 2014 there are a lot of options possible for DR or some extra Configuration options.

In the Old days there was only a failover option in SQL active/passive or if you had multiple instances you could run a instance on every node this could be seen as active/active. en yes mirroring was also an option.

But now the naming is different and there are a lot more configuration options. Remember “ my SQL is running on bare metal much faster “ eh this is not that long ago.  Configurations with a Scale-out file server is not yet common but more and more configurations are using it. Now that SQL Server 2014 can store on CSV. In the following 3 blog post I will show you how to create all this bottom up. easy playground. A lot of terms will pass along like FCI WSFC Azure CSV, FTW SQL LOL

But the Two main options on SQL for clustering are :

AlwaysOn Failover Cluster Instances (SQL Server)

AlwaysOn Availability Groups (SQL Server)


AlwaysOn Failover Cluster Instances (SQL Server)

Failover cluster instance (FCI)  is in short the old active/passive configuration – Protection level SQL Server / instance

As part of the SQL Server AlwaysOn offering, AlwaysOn Failover Cluster Instances leverages Windows Server Failover Clustering functionality to provide local high availability through redundancy at the server-instance level—a failover cluster instance (FCI).

An FCI is a single instance of SQL Server that is installed across Windows Server Failover Clustering nodes and, possibly, across multiple subnets. On the network, an FCI appears to be an instance of SQL Server running on a single computer, but the FCI provides failover from one Windows Server Failover Clustering node to another if the current node becomes unavailable.

An FCI can leverage AlwaysOn Availability Groups to provide remote disaster recovery at the database level.

AlwaysOn Failover Cluster Instances (SQL Server)

As the “SQL Server (MSSQL001)” is installed on two nodes the instances and the DB are fault tolerant but needs shared storage

This is a AlwaysOn Failover Cluster Instances (SQL Server) FCI solution.

When a SQL Server instance is configured to be an FCI (instead of a standalone instance), the high availability of that SQL Server instance is protected by the presence of redundant nodes in the FCI. Only one of the nodes in the FCI owns the Windows Server Failover Clustering resource group at a time. In case of a failure (hardware failures, operating system failures, application or service failures), or a planned upgrade, the resource group ownership is moved to another Windows Server Failover Clustering node. This process is transparent to the client or application connecting to SQL Server and this minimize the downtime the application or clients experience during a failure.

The following lists some key benefits that SQL Server failover cluster instances provide:

  • Protection at the instance level through redundancy

  • Automatic failover in the event of a failure (hardware failures, operating system failures, application or service failures)

  • Zero reconfiguration of applications and clients during failovers


AlwaysOn Availability Groups (SQL Server)

The AlwaysOn Availability Groups feature is a high-availability and disaster recovery solution that provides an enterprise level alternative to database mirroring. An availability group supports a failover environment for a discrete set of user databases, known as availability databases, that fail over together. An availability group supports a set of read-write primary databases and one to four sets of corresponding secondary databases.

Deploying AlwaysOn Availability Groups requires a Windows Server Failover Cluster. To be enabled for AlwaysOn Availability Groups, an instance of SQL Server must reside on a Windows Server Failover Cluster node, and the Windows Server Failover Cluster and node must be online. Furthermore, each availability replica of a given availability group must reside on a different node of the same Windows Server Failover Cluster.

AlwaysOn Availability Groups supports cross-cluster migration of availability groups for deployments to a new Windows Server Failover Clustering. A cross-cluster migration moves one availability group or a batch of availability groups to the new, destination WSFC cluster with minimal downtime.

By implementing AlwaysOn SQL Server FCI an availability replica can be hosted by either a standalone instance of SQL Server or an FCI instance. Only one FCI partner can host a replica for a given availability group.

AlwaysOn Availability Groups does not depend on any form of shared storage. However, if you use a SQL Server failover cluster instance (FCI) to host one or more availability replicas, each of those FCIs will require shared storage as per standard SQL Server failover cluster instance installation.

You might need to configure a Windows Server Failover Clustering (WSFC) cluster to include shared disks that are not available on all nodes. For example, consider a WSFC cluster across two data centers with three nodes. Two of the nodes host a SQL Server failover clustering instance (FCI) in the primary data center and have access to the same shared disks. The third node hosts a stand-alone instance of SQL Server in a different data center and does not have access to the shared disks from the primary data center. This WSFC cluster configuration supports the deployment of an availability group if the FCI hosts the primary replica and the stand-alone instance hosts the secondary replica.


The following lists some key benefits that AlwaysOn Availability Groups provide ( depends on your configuration ):

  • No shared disk needed

  • Only Database protection

  • Zero reconfiguration of applications and clients during failovers


AlwaysOn Failover AG (SQL Server)

As the screenshot shows it hold a availability group with a listner. The configuration is only visible in the SQL server manager

This sounds great new options more but how to configure them and how about Azure In the next post I will show you how to create all this.

In the following I created a Cluster connected to azure with a Site to Site VPN. And will show you the HA options this will be in several steps else it would be a long post.

But along the choices there are a lot of options that can be a problem with your configuration or maybe not the best option. And maybe you need a 3th party product the get the job done. Like Datakeeper my fellow Cluster MVP David Bermingham is SteelEye’s Director of Product Management.

In the next part I will start with AlwaysOn Failover Cluster Instances (SQL Server) Followed By AlwaysOn availability group (SQL Server) and Azure Failovers.

Posted May 14, 2014 by Robert Smit in SQL, SQL Server 2014

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