SQL SERVER – Database Mirroring. Error: 1475, Error: 1478, Error: 1412.

Problem.

When a database mirroring is configured, some error messages are not completely clear when we got it. The following errors are typical while a database mirroring configuration is performed:

Database Mirroring cannot be enabled because the database may have bulk logged changes that have not been backed up. The last log backup on the principal must be restored on the mirror. (Microsoft SQL Server, Error 1475)

The mirror database has insufficient transaction log data to preserve the log backup chain of the principal database. This may happen if a log backup from the principal database has not been restored on the mirror database. (Microsoft SQL Server, Error 1478)

The remote copy of database has not been rolled forwarded to a point in time that is encompassed in the local copy of the transactional log. . (Microsoft SQL Server, Error 1412)

I got the error mentioned above when I try to start the synchronization for database mirroring.

Solution / Fix / Workaround.

To start the synchronization successfully follow the next steps:

1. Principal Instance - Take a full backup and a log backup as well

2. Copy the full/log backups from Principal Instance to Mirror instance

3. Mirror Instance - Restore with NORECOVERY option the full backup

4. Mirror Instance – Apply the log backup

5. Principal Instance - Start synchronization

Enjoy!!