I have installed SQL Server using Failover Clustering on 2 nodes, running Windows Server 2012 R2 Enterprise Edition and SQL Server 2008R2 Standard SP1. Shared storage is provided by an iSCSI NAS device.
If I move the services to node 1, then shutdown node 2, SQL Server continues to run, as expected, on node 1. However, if I then shutdown node 1, and restart it, SQL Server fails to startup with the following error:
The resource has failed to come online due to the failure of one or more provider resources.
Why can't I start SQL Server?
Best Answer
In order for SQL Server services to start as part of a Windows Failover Clustering Service, quorum needs to be attained by at least one node in the cluster. If a two-node cluster has one node down, that node cannot contribute to the quorum, so some other method is necessary for the node that is up to attain quorum. Quorum is essentially a set of votes to see which node gets to run SQL Server. Without quorum, no node can run the service, which is the symptoms you are seeing.
The MSDN page on Failover Clustering quorums states:
You need to configure the failover cluster with one of the following options:
Node majority (no witness) - Only nodes have votes. No quorum witness is configured. The cluster quorum is the majority of voting nodes in the active cluster membership.
Node majority with witness (disk or file share) - Nodes have votes. In addition, a quorum witness has a vote. The cluster quorum is the majority of voting nodes in the active cluster membership plus a witness vote. A quorum witness can be a designated disk witness or a designated file share witness.
No majority (disk witness only) - No nodes have votes. Only a disk witness has a vote. The cluster quorum is determined by the state of the disk witness. The cluster has quorum if one node is available and communicating with a specific disk in the cluster storage. Generally, this mode is not recommended, and it should not be selected because it creates a single point of failure for the cluster.