Backing up SQL Server in an environment with log shipping
Many sites also use the secondary server to off-load certain activities from the primary to minimize its load. However, a backup must not be performed on a secondary (or standby) server. Databases must always be backed up on the primary server and restored on the primary server. This requirement is based on the Microsoft SQL Server restriction that is outlined in Microsoft knowledge base article 311115.
If you try to perform a backup on the secondary server, you see a message in the dbclient log similar to the following:
16:33:26 [1208,2348] <16> CODBCaccess::LogODBCerr: DBMS MSG - ODBC message. ODBC return code <-1>, SQL State <37000>, Message Text <[Microsoft][ODBC SQL Server Driver][SQL Server]Database 'Mumbo' is in warm-standby state (set by executing RESTORE WITH STANDBY) and cannot be backed up until the entire load sequence is completed.>