On an instance of SQL Server, one or more of the following errors may be logged in the SQL Server error log or in the Application log:
Error1:
Error 824 : SQL Server detected a logical consistency-based I/O error: incorrect pageid (expected 1:425920; actual 65535:0). It occurred during a read of page (1:425920) in database ID 2 at offset 0x000000cff80000 in file 'D:\DBName.mdf'. Additional messages in the SQL Server error log or system event log may provide more detail. This is a severe error condition that threatens database integrity and must be corrected immediately. Complete a full database consistency check (DBCC CHECKDB). This error can be caused by many factors; for more information, see SQL Server Books Online.
Error 2:
2011-02-24 00:20:32.55 spid65 Error: 605, Severity: 21, State: 3.
2011-02-24 00:20:32.55 spid65 Attempt to fetch logical page (1:17479052) in database 8 failed. It belongs to allocation unit 0 not to 72057610609819648.
Error 3:
Error 823 The operating system returned error incorrect pageid (expected 1:306208; actual 65535:0) to SQL Server during a read at offset 0x00000095840000 in file 'R:\DBName.mdf'. Additional messages in the SQL Server error log and system event log may provide more detail. This is a severe system-level error condition that threatens database integrity and must be corrected immediately. Complete a full database consistency check (DBCC CHECKDB). This error can be caused by many factors; for more information, see SQL Server Books Online.
Error 4:
Error 18400 The background checkpoint thread has encountered an unrecoverable error. The checkpoint process is terminating so that the thread can clean up its resources. This is an informational message only. No user action is required.
Error 5:
Backup detected log corruption in database DBName. Context is FirstSector. LogFile: 2 'R:\DBName.LDF' VLF SeqNo: x3c1c3 VLFBase: x6a850000 LogBlockOffset: x6bbcde00 SectorStatus: 2 LogBlock.StartLsn.SeqNo: x560053 LogBlock.StartLsn.Blk: x2d0043 Size: x53 PrevSize: x5c.
Additionally, if you run the DBCC CHECKDB command, it may indicate database consistency problems.