SQL Server allows you to use a LSN (Log Sequence Number) that can be used as a recovery point for database restoration before the point of failure. When you perform differential backup process for your database, it is dependent upon a bitmap page that holds a bit per extent. Thus, corresponding changes are required to be marked in this differential backup bitmap or else will generate errors in database pages. You might need to restore the damaged database from the latest backup present. But sometimes, you don’t get complete restoration results from your backup as it is incomplete or invalid. In such situations, you should use advanced MDF Repair tools that use powerful scanning algorithms to repair damaged SQL Server database.
As an instance, you might receive the below error with your SQL Server database:
Server: Msg 2515, Level 16, State 1
Page P_ID, object ID O_ID, index ID I_ID has been modified but is not marked modified in the differential backup bitmap.
Cause
The above error is a result of database check that is performed only if the differential bitmap is free from errors. The error suggests that the page specified with P_ID has a Log Sequence Number and has got a higher value than differential base Logic Sequence Number in FCB (File Control Block) of file or differential reference Log Sequence Number in BackupManager (whichever is the more recent value). The error occurs when this change has not been marked in differential backup bitmap. Since repair process doesn’t depend upon the number of pages included in the database, the P_ID refers to the first page of database.
Solution
To recover from such situations, you need to deploy these methods:
.Check and fix your system for possible hardware issues through Windows, application and SQL Server™ error logs
.Restore the damaged database from the latest backup available
.Run DBCC CHECKDB without using any repair clause to determine extent of corruption and repair clause. Next, again execute DBCC CHECKDB but with the suggested repair clause. But this might cause data loss
.For safe repair mdf file, use commercial tools to repair and restore damaged SQL databases. MDF Repair tools are built with powerful technology and provide you self-explanatory user interface and safe repair options.
Stellar Phoenix SQL Recovery is an advanced mdf repair utility to repair damaged databases created with SQL Server 2008, 2005 and 2000. It is a fully-competent tool that restores all database components including triggers, stored procedures, views, rules and more. It is compatible with Windows Vista, XP, 2003, 2000 and NT.