geramkumar (8/19/2010)
I am a SQL server DBA concentrating more in Internals and performance tuning area.like to know in which scenario a page will be corrupted? how sql server understands that the page is corrupted?
Corruption means that a page's structure is no the way it should be. Either there's incorrect values for parts of the page, the page checksum is wrong, the page is completely unreadable (The OS returns an error when asked for it), or one or more rows on the page have incorrect values in places
i know almost 70% of data corruption cases can be rectified without or with minimum data loss.
I wouldn't put a figure on it. I do know that, with an appropriate backup strategy and regular integrity checks, almost all corruption cases can be recovered without data loss. That depends on knowing about the corruption early enough that restoring from backup is an option (and on having a backup to restore from)
Take a look at this article. http://www.sqlservercentral.com/articles/65804/
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability