因為數據比較的重要，並且數據容量也不大，我們要求的備份策略是每天在磁帶機做POS_DB的全備份（一個星期7天一個循環），在晚上還
在硬盤上做全部備份（MASTER,MSDB,POS_DB).這樣保持雙重的保險。
1.故障爆發：
2003－12－26 13:00
客戶報告所有的POS死機和SERVER運行速度非常的慢。經過重新啟動服務器（啟動到檢查RAID卡時開始報警）我們發現在WINDEOWS 2000
SERVER的“系統日志”中有這樣的信息：
Error: 823, Severity: 24, State: 2
I/O error (torn page) detected during read at offset 0x0000001bf96000 in file D :\DATA\POS_DB.mdf'.
SQLSERVER的“錯誤日志”中有這樣的信息：
2003-12-10 03:34:22.23 spid56 Error: 823, Severity: 24, State: 2
2003-12-10 03:34:22.23 spid56 I/O error (torn page) detected during read at offset 0x00000074964000 in file
'D:\DATA\POS_DB.mdf'..
來自msdn的解釋：
I/O logical check failure: If a read Windows API call or a write Windows API call for a database file is successful, but
specific logical checks on the data are not successful (a torn page, for example), an 823 error is raised. The following
error message is an example of an 823 error for an I/O logical check failure:
2003-09-05 16:51:18.90 spid17 Error: 823, Severity: 24, State: 2
2003-09-05 16:51:18.90 spid17 I/O error (torn page) detected during read at offset 0x00000094004000 in file
'F:\SQLData\mydb.MDF'..
To resolve this problem, first run the DBCC CHECKDB statement on the database that is associated with the file in the
error message. If the DBCC CHECKDB statement reports errors, correct those errors before you troubleshoot this problem. If
the problem persists even after the DBCC CHECKDB errors have been corrected, or if the DBCC CHECKDB statement does not report
any errors, revIEw the Microsoft Windows NT system event log for any system errors or disk-related errors. You can also
contact your hardware vendor to run any appropriate diagnostics.
I/O邏輯檢查失敗：如果有一個Windows程序在讀取和寫數據庫文件時是成功的，但是在詳細的數據邏輯檢查時沒有成功（比如：不完整的
頁），SQLSERVER會返回MSG 823的錯誤。下面就是一個I/O邏輯檢查失敗MSG 823的實例：
2003-09-05 16:51:18.90 spid17 Error: 823,
