A database administrator is evaluating a high availability solution that uses shared storage between two database servers. If the primary server fails, the secondary server can quickly mount the shared storage and take over the database instance. This approach eliminates the need for data replication between servers. Which high availability solution is described?
- ADatabase Mirroring
- BFailover Cluster Instance (FCI)
- CAlways On Availability Groups
- DLog Shipping
Show answer & explanationAnswer & explanation
Correct answer: B. Failover Cluster Instance (FCI)
A Failover Cluster Instance (FCI) uses shared storage, typically a Storage Area Network (SAN), where the database files reside. If one node fails, another node in the cluster can take ownership of the shared storage and bring the database instance online. This eliminates the need for data replication because all nodes access the same data files.
Why the other options are wrong
- A. Database Mirroring explicitly relies on data replication (sending transaction logs) between separate storage systems, not shared storage.
- C. Always On Availability Groups use data replication to maintain copies of databases on separate storage systems, not shared storage for the database files themselves.
- D. Log Shipping involves copying and restoring transaction log backups, which is a form of data replication and does not use shared storage in the manner described.
Failover Cluster Instance (FCI)
A Failover Cluster Instance (FCI) is a single instance of a database server that is installed across multiple Windows Server Failover Cluster (WSFC) nodes and utilizes shared storage. If one node fails, the database instance automatically fails over to another node in the cluster, which takes ownership of the shared storage and brings the instance online.
- Uses shared storage (e.g., SAN).
- Database instance fails over between nodes.
- No data replication needed between nodes; all access same files.
Memory trick: FCI: Shared disk, instant switch, no data replication glitch.