In this blog post, let’s learn about the error message “1478 – The mirror database, “%.*ls”, 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 taken or has not been restored on the mirror database.” in Microsoft SQL Server, the reason why it appears and the solution to fix it.
SQL Server Error Message
1478 – The mirror database, “%.*ls”, 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 taken or has not been restored on the mirror database.
Reason for the Error
The SQL Server Error Msg 1478 occurs when there is not enough transaction log data available in a mirrored database to preserve the log backup chain of the primary database. A mirrored database is a backup copy of the primary database kept in sync with the primary database by transferring transaction logs from the primary database to the mirrored database.
In simpler terms, this error means that the mirrored database does not have enough information to keep up with the primary database, which can cause problems if you need to switch to the mirrored database due to issues with the primary database.
Solution
To resolve this error, take a log backup of the primary database and restore it to the mirrored database to ensure it has the latest transaction logs. Alternatively, you may need to adjust the mirroring settings to ensure that transaction logs are transferred more frequently between the primary and mirrored databases so that the mirrored database can stay updated with changes made to the primary database.
