SQL now is part for almost every Microsoft product so the availability of it becoming very critical I will describe the failover cluster as a method of SQL high availability . I have to say also this is not the only method .some use database mirroring and some use the database replication .there are so many solutions to any given Issue every thing depends on your requirements and network design .
SQL had introduced lately more that one option in installing failover cluster so without delay let’s jump in
SQL Server Failover Cluster Installation options
Option 1: Integrated installation with Add Node
SQL Server integrated failover cluster installation consists of two steps:
Create and configure a single-node SQL Server failover cluster instance. At the completion of a successful configuration of the node, you have a fully functional failover cluster instance. At this time it does not have high-availability because there is only one node in the failover cluster.
On each node to be added to the SQL Server failover cluster, run Setup with Add Node functionality to add that node.
Option2: Advanced/Enterprise installation
SQL Server Advanced/Enterprise failover cluster installation consists of two steps:
On each node that will be part of the SQL Server failover cluster, run Setup with Prepare Failover Cluster functionality. This step prepares the nodes ready to be clustered, but there is no operational SQL Server instance at the end of this step.
After the nodes are prepared for clustering, run Setup on the node that owns the shared disk with the Complete Failover Cluster functionality. This step configures and completes the failover cluster instance. At the end of this step, you will have an operational SQL Server failover cluster instance.
Install Microsoft Distributed Transaction Coordinator
Before installing SQL Server on a failover cluster, determine whether the Microsoft Distributed Transaction Coordinator (MSDTC) cluster resource must be created. If you are installing only the Database Engine, the MSDTC cluster resource is not required. If you are installing the Database Engine and SSIS, Workstation Components, or if you will use distributed transactions, you must install MSDTC. Note that MSDTC is not required for Analysis Services-only instances.
Configure Microsoft Distributed Transaction Coordinator
After you install the operating system and configure your cluster, you must configure MSDTC to work in a cluster by using the Cluster Administrator. Failure to cluster MSDTC will not block SQL Server Setup, but SQL Server application functionality may be affected if MSDTC is not properly configured.
During SQL Server 2008 R2 Failover Cluster installation, computer object (Active Directory computer accounts) for the SQL Server Network Resource Name is created. In a Windows 2008 cluster, the cluster name account (computer account of the cluster itself) needs to have permissions to create computer objects.
note : SQL Server failover clustering is not supported where cluster nodes are domain controllers
we start by installing SQL prerequisites
Next we start the SQL cluster
we only need to cluster the database
we create a new group for the SQL
you must use domain account you can not use local account (system, service or network )
the locations of the installation must be on the shared storage
Now for the second node
We type in the password the accounts must be the same on both nodes
And we done
This Post is the steps taken from Microsoft TechNet but with rearranging the topics to seem a bit logical for someone that does not know the technology (there is no point in reinventing the wheel). I also added my personal experience into it .
The soul purposes of this guide is to give some idea about the technology .you can use it to deploy your own Solution but I don’t recommended it as every infrastructure is a bit different than the other . Please remember the golden rules “60% planning 30% deployment 10% maintenance “. this rule saved me a lot of pain and grief .
SQL clusters is not easy thing to fix I recommend that you give Microsoft guide a good read before you start ( it’s a bit large ~175 page )