What is Checksum Function in SQL Server? As you are aware checksum is new functionality offered by Microsoft in SQL Server 2005 that gives you advanced mechanism to identify any corruptions of database pages which can take place in I/O path. There can be multiple reasons for database corruption which can not be covered by of SQL Server itself.
Checksum Errors: When you try to start the SQL Server and if you are getting the following message:
Error: 824, Severity: 24, State: 2. 2010-03-09 06:12:35.51 spid7s SQL Server detected a logical consistency-based I/O error: incorrect checksum (expected: 0x3ee24b20; actual: 0x8d0681bd). It occurred during a read of page (1:375) in database ID 1 at offset 0x000000002ee000 in file 'C: Program FilesMicrosoft SQL Server'
The reason you are getting this error is because your database has encountered a logical consistency problem. These logical consistency problems are reported through Error 824 called as Checksum Error. This logical consistency includes checksum, Torn Page, Short Transfer, Bad Page Id, Stale Read, and Page Audit Failure.
Reasons for SQL Server Database Corruption: Possible reasons which are outside the control of SQL Server are listed below.
Out of order or Faulty I/O device
Incomplete write of database page due to power loss
How to Solve Checksum Error in SQL Server? In the above situations Checksum function allows SQL Server to identify the database corruption. You also need to be aware that checksum functionality only allows you to identify the causes of page corruption and it does not fix them automatically. By using the information provided by Checksum you can identify, remove the faulty I/O device. Now if you want to restore the existing corrupted or damaged database then you can use SysTools SQL Recovery Tool which comes very useful to restore all your corrupted databases. After you restore corrupted SQL database using SQL Repair tool then you should not face Checksum Error again.