You recently upgraded a SharePoint Server 2010 server farm to SharePoint Server 2013. The farm contains many sites. The sites contain frequently updated content. You need to ensure that users can…

Database mirroring maintains a synchronized standby copy for failover purposes, but the mirror database is not directly accessible for read operations or isolated upgrade testing the way a log shipping secondary database is.

SQL Server Log Shipping continuously ships transaction log backups from the primary SharePoint content database to a secondary server, keeping a close-to-current copy available for read and test operations. Site collection administrators can run upgrade evaluations (demo upgrades) against this secondary copy, placing no additional read or write load on the production database and thus minimizing the impact on users still working in SharePoint 2010 compatibility mode.

AlwaysOn Availability Groups provide high availability and readable secondary replicas, but they are designed for failover and load distribution rather than creating an isolated copy of a content database specifically for upgrade evaluation.

SQL Server Snapshots create a point-in-time read-only copy on the same server instance as the primary database, which would increase I/O resource consumption on the production server and not minimize impact on users.