Database Mirroring: In SQL Server 2008, you can use the feature of database mirroring between two databases. It can help in the data loss situations where a database damages for some reason; you can back up your database from the mirror database.
Transaction Log Files Removed Accidentally: If by chance, you remove the transaction log files; the database mirroring session can interrupt. This causes the Principal Server to fail and you will not be able to restore the data from mirror server. This can cause corruption damaging the database.
A Possible Scenario: Consider a practical scenario where you are using SQL Server 2008 SP1 (Service Pack 1) or MS SQL Server 2008. You configure mirroring between 2 databases.
Transaction Log Files Removed – Errors Encountered: You run ALTER DATABASE command with REMOVE FILE clause for removing the transaction log files on the main SQL Server database. This can abort database mirroring session, which you cannot resume. You can also receive the following message: “Location:” logmgr. cpp “: 3350
Expression: headLFCB-> lfcb_startOffset GetSize () * (ULONGLONG) PAGESIZE”
After that, you get the below error message in SQL Server event log logged:
“spid23s A system has failed. Check the SQL Server error log for more details. Typically, an assertion is by a software bug or data corruption. To check for any damage to the database, DBCC CHECKDB. If you send causes agreed to dumps to Microsoft during setup, a mini dump will be sent to Microsoft. An update is available from Microsoft in the latest service pack or in a QFE from Technical Support.”
Cause behind SQL MDF Corruption: The main cause behind problem can be the incorrect log on mirror-space tracking database or due to SQL database MDF file corruption.
How to Restore SQL Database? First check the cause of the problem and accordingly you can use the below mentioned resolutions methods.
1. Problem caused due to incorrect log space tracking: If the above mentioned problem has been caused due to incorrect log space tracking, then you can load the latest SQL Server update and then install it on your machine.
2. Problem caused due to MDF corruption: However, if there is MDF corruption issue, then you have to go for SQL Server database recovery. SQL recovery process can be performed using an advanced and effective third-party tool like SysTools SQL Recovery software. You can easily restore SQL master database using this simple and intuitive SQL Server disaster recovery (http://www.sqlrecovery.co.uk/how-to-restore-an-sql-database) tool. The application employs advanced scanning techniques to ensure accurate and rapid SQL recovery in almost all types of corruption cases. You can use this tool to restore SQL 2000 database also as it supports all major SQL versions.