一、备份Master 及相关的系统数据库
由于系统数据库对Sql Server来说尤其重要，为了确保SQL SERVER系统的正常运行，除了日常备份用户的数据库之外，我们还需要备份系统数据库，如对Master，Model，Msdb（TempDB不需备份）进行完整备份
二、还原Master数据库
如果系统配置丢失或Master出现问题，可以进入单用户模式进行还原；如果出现下列情况，必须重新生成损坏的 master 数据库：
A. master 数据库的当前备份不可用。
B. 存在 master 数据库备份，但由于 Microsoft SQL Server 实例无法启动，因此无法还原该备份。
1、重新生成 master 数据库：
注意：
在 SQL Server 2005 中已废止 Rebuildm.exe 程序。若要重新生成 master 数据库，请使用 setup.exe。
1、 Start /wait setup.exe /qn INSTANCENAME=<InstanceName> REINSTALL=SQL_Engine REBUILDDATABASE=1 SAPWD=<NewStrongPassword>
例：start /wait e:setup.exe /qn INSTANCENAME=mssqlserver REINSTALL=SQL_Engine REBUILDDATABASE=1 SAPWD=abc123@!@
注：INSTANCENAME：指定实例名，默认实例则用mssqlserver表示
REINSTALL：指定引擎
SAPWD：强密码
Setup.exe：指定光盘1中的根目录下的文件
/qn 开关用于取消所有安装程序对话框和错误消息。如果指定 /qn 开关，则所有安装程序消息（包括错误消息）都将写入安装程序日志文件。有关日志文件的详细信息，请参阅如何查看 SQL Server 2005 安装日志文件。
指定 /qb 开关将显示基本的安装程序对话框。还会显示错误消息。

2、 还原Master备份
先进入单用户模式，系统默认没有设置PATH，先进入CMD，进入“C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLBinn”，执行SQLSERVR.EXE –M
打开SSMS工具，先断开连接，再新建查询，执行以下命名还原
USE master
GO
RESTORE DATABASE master
FROM disk='c:master.bak'
GO

开始实验了~~~
MASTER重新生成
为了模拟MASTER数据库坏了,我们就删除MASTER数据库(要停止SQL SERVER服务才能删除)在我的电脑,C: PROGRAM FILESMICROSOFT SQL SERVERMSSQL.1MSSQLDATE 中删除MASTER.MDF
重新生成MASTER
1.首先在CMD中输入
start /wait setup.exe /qn INSTANCENAME=<InstanceName> REINSTALL=SQL_Engine REBUILDDATABASE=1 SAPWD=<NewStrongPassword>

其中的 SETUP.EXE为启动光盘的路径,我这里的是 E:SETUP.EXE /QN

我这里的为默认实例所以其中的<INSTANCENAME>用 MSSQLSERVER代替

最后的<NewStrongPassword>为密码我设密码为abc123@!@,所以就用abc123@!@代替<NewStrongPassword>

若没有返回错误,我们就可以到我的电脑中C: PROGRAM FILESMICROSOFT SQL SERVERMSSQL.1DATE上面又有MASTER.MDF了

接下来进入目录
单用户模式
启动SSMS工具,新建查询
输入命令
启动服务(MSSQL SERVER)
打开SSMS
连接到数据库后就可以发现数据库中的数据又回来了

以下是我在命令行下搞的命令,我用记事本的方式全部复制下来了,为了不传附件,我就直接粘贴到下面了
Microsoft Windows [版本 5.2.3790]
(C) 版权所有 1985-2003 Microsoft Corp.
C:Documents and SettingsAdministrator>start /wait e:setup.exe /qn INSTANCENAME=mssqlserver REINSTALL=SQL_Engine REBUILDDATABASE=1 SAPWD=abc123@!@
C:Documents and SettingsAdministrator>cd C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLBinn
C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLBinn>sqlservr.exe -m
2008-04-18 15:47:46.56 Server Authentication mode is MIXED.
2008-04-18 15:47:46.59 Server Microsoft SQL Server 2005 - 9.00.1399.06 (Intel X86)
Oct 14 2005 00:33:37
Copyright (c) 1988-2005 Microsoft Corporation
Enterprise Edition on Windows NT 5.2 (Build 3790: Service Pack 1)
2008-04-18 15:47:46.59 Server (c) 2005 Microsoft Corporation.
2008-04-18 15:47:46.59 Server All rights reserved.
2008-04-18 15:47:46.59 Server Server process ID is 3984.
2008-04-18 15:47:46.59 Server Logging SQL Server messages in file 'C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLLOGERRORLOG'.
2008-04-18 15:47:46.59 Server This instance of SQL Server last reported using a process ID of 764 at 2008-4-18 15:46:40 (local) 2008-4-18 7:46:40 (UTC). This is an informational message only; no user action is required.
2008-04-18 15:47:46.60 Server Registry startup parameters:
2008-04-18 15:47:46.60 Server -d C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLDATAmaster.mdf
2008-04-18 15:47:46.60 Server -e C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLLOGERRORLOG
2008-04-18 15:47:46.60 Server -l C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLDATAmastlog.ldf
2008-04-18 15:47:46.62 Server Command Line Startup Parameters:
20　　2008-04-18 15:47:47.95 服务器 Attempting to recover in-doubt distributed transactions involving Microsoft Distributed Transaction oordinator (MS DTC).
This is an informational message only. No user action is required.
2008-04-18 15:47:47.96 服务器 Database Mirroring Transport is disabled in the endpoint configuration.
2008-04-18 15:47:47.96 spid5s Warning ******************
2008-04-18 15:47:47.96 spid5s SQL Server started in single-user mode. This an informational message only. No user action is required.
2008-04-18 15:47:47.99 spid5s Starting up database 'master'.
2008-04-18 15:47:48.17 spid5s Recovery is writing a checkpoint in database 'master' (1). This is an informational message only. No user action is required.
2008-04-18 15:47:48.28 spid5s SQL Trace ID 1 was started by login "sa".
2008-04-18 15:47:48.32 spid5s Starting up database ssqlsystemresource'.
2008-04-18 15:47:48.76 spid5s Server name is 'VM01'. This is an informational message only. No user action is required.
2008-04-18 15:47:48.78 spid8s Starting up database 'model'.
2008-04-18 15:47:49.20 服务器 A self-generated certificate was successfully loaded for encryption.
2008-04-18 15:47:49.23 服务器 Server is listening on [ 'any' <ipv4> 1433].
2008-04-18 15:47:49.24 服务器 Server local connection provider is ready to accept connection on [ \.pipeSQLLocalMSSQLSERVER ].
2008-04-18 15:47:49.24 服务器 Server local connection provider is ready to accept connection on [ \.pipesqlquery ].
2008-04-18 15:47:49.28 服务器 Server is listening on [ 127.0.0.1 <ipv4>1434].
2008-04-18 15:47:49.28 服务器 Dedicated admin connection support was established for listening locally on port 1434.
2008-04-18 15:47:49.29 服务器 The SQL Network Interface library could not register the Service Principal Name (SPN) for the SQL Server service. Error: 0x54b. Failure to register an SPN may cause integrated authentication to fall back to NTLM instead of Kerberos. This is an informational message. Further action is only required if Kerberos authentication is required by authentication policies.
2008-04-18 15:47:49.31 服务器 SQL Server is now ready for client connections. This is an informational message; no user action is required.
2008-04-18 15:47:49.40 spid5s Starting up database 'msdb'.
2008-04-18 15:47:49.68 spid8s Clearing tempdb database.
2008-04-18 15:47:49.93 spid5s Recovery of any in-doubt distributed transactions involving Microsoft Distributed Transaction Coordinator (MS DTC) has completed. This is an informational message only. No user action is required.
2008-04-18 15:47:50.57 spid8s Starting up database 'tempdb'.
2008-04-18 15:47:50.76 spid5s Recovery is complete. This is an informational message only. No user action is required.
2008-04-18 15:56:22.34 spid51 SQL Trace was stopped due to server shutdown. Trace ID = '1'. This is an informational message only; no user action is required.
2008-04-18 15:56:22.40 服务器 The SQL Network Interface library could not deregister the Service Principal Name (SPN) for the SQL Server service. Error: 0x54b. Administrator should deregister this SPN manually to avoid client authentication errors.
C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLBinn>

打开SSMS工具，先断开连接，再新建查询，执行以下命名还原
USE master
GO
RESTORE DATABASE master
FROM disk='C:Program FilesMicrosoft SQL ServerMSSQL.1 MSSQLBackupmaster.bak'
GO

数据库中的显示的消息应为：
已为数据库 'master'，文件 'master' (位于文件 1 上)处理了 376 页。
已为数据库 'master'，文件 'mastlog' (位于文件 1 上)处理了 6 页。
已成功地还原了 master 数据库。正在关闭 SQL Server。
SQL Server 正在终止此进程。
则表示master数据库还原成功,启动服务后进入SSMS即可看到master数据库了。
08-04-18 15:47:46.62 Server -m
2008-04-18 15:47:46.64 服务器 SQL Server is starting at normal priority base (=7). This is an informational message only. No user action is required.
2008-04-18 15:47:46.67 服务器 Detected 1 CPUs. This is an informational message; no user action is required.
2008-04-18 15:47:46.78 服务器 Using dynamic lock allocation. Initial allocation of 2500 Lock blocks and 5000 Lock Owner blocks per node. This is an informational message only. No user action is required.
2008-04-18 15:47:46.84 服务器 Attempting to initialize Microsoft Distributed Transaction Coordinator (MS DTC). This is an informational message only. No user action is required.