曾经遇到过一个用户MSDB数据库非常大，让我帮忙查查是什么原因。使用sp_spaceused找出了所有表的数据大小，发现问题是SQL Server备份和还原历史表数据太大。用户经常会做日志备份，但是从来没有清除过历史记录。后来在设置了维护计划定期清除备份记录，问题就不在发生了。
这里列出了查询SQL Server备份还原记录的语句以及如何清理数据库备份还原的脚本：
--查询SQL Server备份历史
SELECT
CONVERT(CHAR(100),SERVERPROPERTY('Servername'))ASServer,
msdb.dbo.backupset.database_name,
msdb.dbo.backupset.backup_start_date,
msdb.dbo.backupset.backup_finish_date,
msdb.dbo.backupset.expiration_date,
CASE msdb..backupset.type
WHEN 'D' THEN 'Database'
WHEN 'L' THEN 'Log'
END ASbackup_type,
msdb.dbo.backupset.backup_size,
msdb.dbo.backupmediafamily.logical_device_name,
msdb.dbo.backupmediafamily.physical_device_name,
msdb.dbo.backupset.nameASbackupset_name,
msdb.dbo.backupset.description
FROM msdb.dbo.backupmediafamily
INNER JOIN msdb.dbo.backupsetONmsdb.dbo.backupmediafamily.media_set_id=msdb.dbo.backupset.media_set_id
ORDER BY
msdb.dbo.backupset.database_name,
msdb.dbo.backupset.backup_finish_date
-----查询SQLServer还原历史
select bus.server_nameas'server',rh.restore_date,bus.database_nameas'database',
CAST(bus.first_lsnASVARCHAR(50))asLSN_First,
CAST(bus.last_lsnASVARCHAR(50))asLSN_Last,
CASE rh.[restore_type]
WHEN 'D'THEN'Database'
WHEN 'F'THEN'File'
WHEN 'G'THEN'Filegroup'
WHEN 'I'THEN'Differential'
WHEN 'L'THEN'Log'
WHEN 'V'THEN'Verifyonly'
END ASrhType
FROM msdb.dbo.backupsetbus
INNER JOINmsdb.dbo.restorehistoryrhON rh.backup_set_id=bus.backup_set_id
---清除20120101之前所有的备份还原记录（没有参数指定只删除备份或者欢迎记录）
use msdb
go
exec sp_delete_backuphistory@oldest_date='20121010'
--删除'AdventureWorks2012'数据库的备份还原记录（没有参数指定保留日期，All或者None）
USE msdb;
GO
EXEC sp_delete_database_backuphistory@database_name='AdventureWorks2012';
http://blog.csdn.net/kevinsqlserver/article/details/8087293