今天，项目组一女司机在维护一生产服务器过程中，犯了一个大傻，下午15时左右，从网上拷贝了一个语句，在其本人“莫名其妙”的情况下，就对生产服务器执行，结果导致SQLServer实例停止并且无法启动，所有应用全部不能访问；
当生产部门发现问题并反馈时，她检查发现SQLServer不能连接（SQL服务停止），遂启动服务（当然报错），然后重新多次启动（从SQL错误日志文件可以看到）....，
折腾到17:30左右，实在挺不住了，找到我(焦急的)反应“sqlserver 的服务不能开启连不上数据库是怎么回事”，
1、废话少说，先远程连上服务器，查看SQL错误日志（D:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Log\ERRORLOG），
下面是详细日志，红色字体是错误部分
2017-08-14 15:10:02.48 Server (c) Microsoft Corporation.
2017-08-14 15:10:02.48 Server All rights reserved.
2017-08-14 15:10:02.48 Server Server process ID is 2896.
2017-08-14 15:10:02.48 Server System Manufacturer: 'LENOVO', System Model: 'Lenovo System x3850 X6 -[6241AC1]-'.
2017-08-14 15:10:02.48 Server Authentication mode is MIXED.
2017-08-14 15:10:02.48 Server Logging SQL Server messages in file 'd:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Log\ERRORLOG'.
2017-08-14 15:10:02.48 Server The service account is 'NT Service\MSSQLSERVER'. This is an informational message; no user action is required.
2017-08-14 15:10:02.48 Server Registry startup parameters:
-d d:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\master.mdf
-e d:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Log\ERRORLOG
-l d:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\mastlog.ldf
2017-08-14 15:10:02.48 Server Command Line Startup Parameters:
-s "MSSQLSERVER"
2017-08-14 15:10:02.68 Server SQL Server detected 4 sockets with 8 cores per socket and 16 logical processors per socket, 64 total logical processors; using 40 logical processors based on SQL Server licensing. This is an informational message; no user action is required.
2017-08-14 15:10:02.68 Server SQL Server is starting at normal priority base (=7). This is an informational message only. No user action is required.
2017-08-14 15:10:02.68 Server Detected 130959 MB of RAM. This is an informational message; no user action is required.
2017-08-14 15:10:02.68 Server Using conventional memory in the memory manager.
2017-08-14 15:10:03.98 Server This instance of SQL Server last reported using a process ID of 14064 at 2017/8/14 15:06:38 (local) 2017/8/14 7:06:38 (UTC). This is an informational message only; no user action is required.
2017-08-14 15:10:03.99 Server Node configuration: node 0: CPU mask: 0x000000000000ffff:0 Active CPU mask: 0x000000000000ffff:0. This message provides a description of the NUMA configuration for this computer. This is an informational message only. No user action is required.
2017-08-14 15:10:03.99 Server Node configuration: node 1: CPU mask: 0x00000000ffff0000:0 Active CPU mask: 0x00000000ffff0000:0. This message provides a description of the NUMA configuration for this computer. This is an informational message only. No user action is required.
2017-08-14 15:10:03.99 Server Node configuration: node 2: CPU mask: 0x0000ffff00000000:0 Active CPU mask: 0x000000ff00000000:0. This message provides a description of the NUMA configuration for this computer. This is an informational message only. No user action is required.
2017-08-14 15:10:03.99 Server Node configuration: node 3: CPU mask: 0xffff000000000000:0 Active CPU mask: 0x0000000000000000:0. This message provides a description of the NUMA configuration for this computer. This is an informational message only. No user action is required.
2017-08-14 15:10:04.00 Server 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.
2017-08-14 15:10:04.00 Server Lock partitioning is enabled. This is an informational message only. No user action is required.
2017-08-14 15:10:09.06 Server Failed allocate pages: FAIL_PAGE_ALLOCATION 1
...
2017-08-14 15:10:09.06 Server 错误: 17300，严重性: 16，状态: 1。(参数:)。所显示的错误消息非常简洁，因为在格式设置期间有错误。跟踪、ETW 和通知等均被跳过。
...
2017-08-14 15:10:09.06 Server 错误: 17312，严重性: 16，状态: 1。(参数:)。所显示的错误消息非常简洁，因为在格式设置期间有错误。跟踪、ETW 和通知等均被跳过。
...
2017-08-14 15:10:09.06 Server 错误: 33086，严重性: 10，状态: 1。(参数:)。所显示的错误消息非常简洁，因为在格式设置期间有错误。跟踪、ETW 和通知等均被跳过。
...
2、问题分析，询问小妹在15:10分左右其对服务器作了什么操作，她发来一串语句，
--修改过内存的
exec sp_configure 'show advanced options', 1
--设置最大内存值，清除现有缓存空间
exec sp_configure 'max server memory', 256
EXEC ('RECONFIGURE')
--设置等待时间
WAITFOR DELAY '00:00:01'
--重新设置最大内存值
EXEC sp_configure 'max server memory', 4096
EXEC ('RECONFIGURE')
--关闭高级配置
exec sp_configure 'show advanced options',0
GO
我一看简直就要晕了，这是个生产服务器啊，总内存128GB，数据1TB左右，怎么能限制到4G呢
心里先平静一下，问她知道这个语句是干嘛的不，她说知道" 设置内存的参数，我就限制了一下服务器内存,然后服务器就停了"....
3、很显然问题原因是：限制内存并应用后，SQLServer内存不足自动停止，并且无法正常启动之
4、解决，以最小模式启动SQLServer实例，修改内存限制
考虑到有多个应用从不同的服务器连接本SQLServer实例，首先做一些外围处理（禁止应用程序连接本实例），避免它们干扰修复过程
-- 关闭本地服务器（连接该实例）的应用程序，
-- 对于跨服务器访问的，在防火墙中关闭SQLServer端口
--1.开启一个cmd窗口 窗口1，-f最小模式启动实例
cd /D C:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Binn\sqlservr.exe
sqlservr.exe -f -sMSSQLSERVER
MSSQLSERVER 默认实例名，可修改为你实际实例名修改
--2.cmd窗口2 （窗口1运行后）立即运行下面命令进入 命令行模式
sqlcmd -E -sMSSQLSERVER
--修复，就本故障来说，修改内存最大值为不限制，
EXEC sp_configure 'show advanced options', '1' RECONFIGURE WITH OVERRIDE;
EXEC sp_configure 'max server memory', 2147483647 RECONFIGURE WITH OVERRIDE;
EXEC sp_configure 'show advanced options', '0' RECONFIGURE WITH OVERRIDE;
GO
-- 3.关闭cmd窗口1，正常启动SQLServer实例
启动成功则OK，如果启动不成功，检查错误日志修复其它参数，直至启动成功。
启动成功后可根据需要重新调整合适的参数，（毕竟紧急情况下是以先解决问题为主）