SQL Server 2008中的完整备份不会中断日志链。它仅复位差分base-lsn。
您还可以仅从副本还原后还原日志备份。以下脚本演示了这一点：
CREATE DATABASE BakTst13;
GO
ALTER DATABASE BakTst13 SET RECOVERY FULL;
GO
USE BakTst13;
GO
CREATE TABLE dbo.tst(id INT IDENTITY(1,1));
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Full_1' WITH INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP LOG BakTst13
TO DISK = 'BakTst13_Log_1' WITH INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Full_2' WITH INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Full_C' WITH COPY_ONLY,INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP LOG BakTst13
TO DISK = 'BakTst13_Log_2' WITH INIT,FORMAT;
GO
USE tempdb;
GO
DROP DATABASE BakTst13;
GO
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Full_1' WITH NORECOVERY;
RESTORE LOG BakTst13 FROM DISK='BakTst13_Log_1' WITH NORECOVERY;
RESTORE LOG BakTst13 FROM DISK='BakTst13_Log_2' WITH RECOVERY;
GO
SELECT * FROM BakTst13.dbo.tst;
GO
DROP DATABASE BakTst13;
GO
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Full_C' WITH NORECOVERY;
RESTORE LOG BakTst13 FROM DISK='BakTst13_Log_2' WITH RECOVERY;
GO
SELECT * FROM BakTst13.dbo.tst;
GO
DROP DATABASE BakTst13;
它创建一个数据库和一个表，并向该表中插入50行。在这些插入之间，按此顺序进行几个备份：
- 充分
- 记录
- 充分
- 完全复制
- 记录
接下来，将数据库删除并还原，如下所示：
- 第一满
- 第一日志
- 第二日志
以下SELECT说明还原成功。
这表明a COP_ONLY和正常的完全备份都不会中断日志链。
然后，再次删除数据库并按以下方式还原：
- 仅复制完整
- 第二日志
之后SELECT再次展示成功。
这说明您可以将COPY_ONLY完整备份用作日志还原的基础。
差异测试
我也创建了一个DIFFERENTIAL版本：
CREATE DATABASE BakTst13;
GO
ALTER DATABASE BakTst13 SET RECOVERY FULL;
GO
USE BakTst13;
GO
CREATE TABLE dbo.tst(id INT IDENTITY(1,1));
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Full_1' WITH INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Diff_1' WITH DIFFERENTIAL,INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Full_2' WITH INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Diff_2' WITH DIFFERENTIAL,INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Full_C' WITH COPY_ONLY,INIT,FORMAT;
GO
INSERT INTO dbo.tst DEFAULT VALUES
GO 10
GO
BACKUP DATABASE BakTst13
TO DISK = 'BakTst13_Diff_3' WITH DIFFERENTIAL,INIT,FORMAT;
GO
USE tempdb;
GO
DROP DATABASE BakTst13;
GO
RAISERROR('------> Starting restore F1, D1, D2',0,1)WITH NOWAIT;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Full_1' WITH NORECOVERY;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Diff_1' WITH NORECOVERY;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Diff_2' WITH NORECOVERY;--<--Fails!
GO
DROP DATABASE BakTst13;
GO
RAISERROR('------> Starting restore FC, D3',0,1)WITH NOWAIT;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Full_C' WITH NORECOVERY;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Diff_3' WITH NORECOVERY;--<--Fails!
GO
DROP DATABASE BakTst13;
GO
RAISERROR('------> Starting restore F2, D2, D3',0,1)WITH NOWAIT;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Full_2' WITH NORECOVERY;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Diff_2' WITH NORECOVERY;
RESTORE DATABASE BakTst13 FROM DISK='BakTst13_Diff_3' WITH RECOVERY;
GO
SELECT * FROM BakTst13.dbo.tst;
GO
DROP DATABASE BakTst13;
这将按以下顺序进行备份：
- 第一满
- 一阶微分
- 第二满
- 二阶微分
- 仅复制差异
- 三阶微分
然后，它将尝试以下还原路线：
- 第一满
- 一阶微分
- 二阶微分
步骤3失败，并显示以下错误：
Msg 3136, Level 16, State 1, Line 4
This differential backup cannot be restored because the database has not been restored to the correct earlier state.
这表明正常的完全备份会断开差异链。
接下来，删除数据库，并尝试执行此还原流程：
- 仅复制完整
- 三阶微分
步骤2失败，并出现与上述步骤3相同的错误。这表明仅复制备份不能用作差异还原的基础。
然后再次删除数据库并执行以下还原：
- 第二满
- 二阶微分
- 三阶微分
以下选择证明此还原成功。这表明COPY_ONLY完全备份不会中断差分链。