If it finds a page that has only partially been written to (due to some
sort of hardware failure), it simply flags it as ???torn.???
Checksum validation is a new page-verification technique. It adds a value for each
data page, essentially identifying the exact size in bytes of the page. While this seems like
it would be an expensive operation as far as performance goes, it??™s actually quite efficient
in SQL Server 2005 (if it weren??™t, they wouldn??™t make it the default behavior). It effectively
acts as torn-page detection as well.
The backup process can validate checksums by comparing the value stored in the
database with the value associated with the data page written to disk. However, it doesn??™t
do this by default. If checksum validation is enabled, you can force the backup process to
perform this validation:
BACKUP DATABASE AdventureWorks
TO DISK = 'D:\data\AW.bak'
WITH CHECKSUM
When an error is encountered during checksum validation, SQL Server writes a
record to MSDB..SUSPECT_PAGE. The default behavior is to STOP_ON_ERROR, allowing you to
attempt to correct the problem and continue issuing the same command with the addition
of RESTART.
Pages:
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105