LUW Rollback During Automatic Backup

Immediately before starting an automatic backup, the server may roll back some long-running logical units of work. The logical units of work the server rolls back are those that were active at the time the last backup was made. That is, the logical unit of work was active during the entire time it took to fill 80% of the log and is still active. The server rolls back these long-running logical units of work because they prevent log space from being freed. The application whose logical unit of work is rolled back will receive an error return code. Given a reasonably sized log, logical units of work that span backups often indicate improperly coded applications.