Snr SQL DBA

MUST HAVE SQL Server high availability cluster experience. See definition below.
A SQL Server high availability cluster is a configuration where multiple SQL Server instances are grouped together to provide redundancy and minimize downtime. In the event of a failure on one instance, another instance can seamlessly take over, ensuring continuous database availability. This is typically achieved through technologies like Always On Failover Cluster Instances (FCI) or Always On Availability Groups.
Here's a more detailed explanation:
Key Concepts:

• Redundancy:

High availability clusters provide multiple SQL Server instances, so if one fails, another is ready to take over.

• Failover:

The process where one instance takes over the workload of a failed instance.

• Downtime Minimization:

By quickly switching to a healthy instance, high availability clusters minimize the time users are unable to access the database.

• Active/Passive:

A common setup where one instance (active) handles the workload, while the other (passive) is on standby, ready to take over.

• Active/Active:

Less common, but can involve both instances actively processing workloads, but failing over to one another in case of failure.
Technologies for Implementing High Availability:

• Always On Failover Cluster Instances (FCI):

A standard feature protecting the entire SQL Server instance, including system databases. It requires shared storage accessible by all nodes in the cluster.

• Always On Availability Groups:

A more robust option offering automatic failover with potentially no data loss. It requires the Enterprise Edition of SQL Server and may involve additional complexity.