Using Log Shipping as Part of a Recovery Plan
Beginning in SQL Server 2005, the transaction log backups for a database that is configured for log shipping (a log shipping database) are created by a log shipping backup job. If you use the Maintenance Plan Wizard to create a maintenance plan for a log shipping database, schedule only full backups and differential backups. Do not schedule any transaction log backups in the maintenance plan. This is essential, because log shipping will function incorrectly if a maintenance plan creates a log backup on the database.
To archive transaction log backups as part of your recovery strategy, copy each of the log backups directly from your log shipping backup share to another media for long term storage. Be sure to set your backup retention period to a sufficiently long time to allow you to copy the log files as needed.
You can set the backup retention period by configuring the Delete files older than: setting on the Transaction Log Backup Settings dialog box.