Oracle RMAN全热或冷备份-哪个更快？

哪个RMAN备份更快，完全热还是冷？

它们将大致相同，因为它们都执行大致相同数量的I/O工作。热备份可能会消耗更多的CPU，因为它可能需要对修改后的块做更多的工作，这对于您在平台上进行测试来说足够容易。对于我的机器，没有区别 (当然，它几乎不是活动数据库)

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options


sys@np12
SQL> alter database close;

Database altered.

sys@np12
SQL> exit
Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

C:\Users\hamcdc>rman target /

Recovery Manager: Release 12.1.0.2.0 - Production on Fri Mar 10 07:59:53 2017

Copyright (c) 1982, 2016, Oracle and/or its affiliates.  All rights reserved.

connected to target database: NP12 (DBID=1950473453, not open)

RMAN> backup database;

Starting backup at 100317-075956
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=125 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00009 name=C:\ORACLE\ORADATA\NP12\LOADER01.DBF
input datafile file number=00006 name=C:\ORACLE\ORADATA\NP12\USERS01.DBF
input datafile file number=00007 name=C:\ORACLE\ORADATA\NP12\EXAMPLE01.DBF
input datafile file number=00008 name=C:\ORACLE\ORADATA\NP12\DEMO.DBF
input datafile file number=00003 name=C:\ORACLE\ORADATA\NP12\SYSAUX01.DBF
input datafile file number=00001 name=C:\ORACLE\ORADATA\NP12\SYSTEM01.DBF
input datafile file number=00005 name=C:\ORACLE\ORADATA\NP12\UNDOTBS01.DBF
channel ORA_DISK_1: starting piece 1 at 100317-075957
channel ORA_DISK_1: finished piece 1 at 100317-080012
piece handle=C:\ORACLE\PRODUCT\12.1.0.2\DATABASE\07RUP07T_1_1 tag=TAG20170310T075957 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 100317-080013
channel ORA_DISK_1: finished piece 1 at 100317-080015
piece handle=C:\ORACLE\PRODUCT\12.1.0.2\DATABASE\08RUP08C_1_1 tag=TAG20170310T075957 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
Finished backup at 100317-080015

RMAN> exit


Recovery Manager complete.

C:\Users\hamcdc>sysdba

C:\Users\hamcdc>sqlplus sys/admin as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Fri Mar 10 08:00:26 2017

Copyright (c) 1982, 2016, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options


sys@np12
SQL> startup force
ORACLE instance started.

Total System Global Area 3154116608 bytes
Fixed Size                  3050600 bytes
Variable Size             771752856 bytes
Database Buffers         2365587456 bytes
Redo Buffers               13725696 bytes
Database mounted.
Database opened.
sys@np12
SQL> exit
Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

C:\Users\hamcdc>rman target /

Recovery Manager: Release 12.1.0.2.0 - Production on Fri Mar 10 08:01:25 2017

Copyright (c) 1982, 2016, Oracle and/or its affiliates.  All rights reserved.

connected to target database: NP12 (DBID=1950473453)

RMAN> backup database;

Starting backup at 100317-080128
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=247 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00009 name=C:\ORACLE\ORADATA\NP12\LOADER01.DBF
input datafile file number=00006 name=C:\ORACLE\ORADATA\NP12\USERS01.DBF
input datafile file number=00007 name=C:\ORACLE\ORADATA\NP12\EXAMPLE01.DBF
input datafile file number=00008 name=C:\ORACLE\ORADATA\NP12\DEMO.DBF
input datafile file number=00003 name=C:\ORACLE\ORADATA\NP12\SYSAUX01.DBF
input datafile file number=00001 name=C:\ORACLE\ORADATA\NP12\SYSTEM01.DBF
input datafile file number=00005 name=C:\ORACLE\ORADATA\NP12\UNDOTBS01.DBF
channel ORA_DISK_1: starting piece 1 at 100317-080129
channel ORA_DISK_1: finished piece 1 at 100317-080144
piece handle=C:\ORACLE\PRODUCT\12.1.0.2\DATABASE\09RUP0AP_1_1 tag=TAG20170310T080128 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 100317-080145
channel ORA_DISK_1: finished piece 1 at 100317-080146
piece handle=C:\ORACLE\PRODUCT\12.1.0.2\DATABASE\0ARUP0B8_1_1 tag=TAG20170310T080128 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 100317-080146

RMAN>
复制

但是当你考虑冷备份的缺点时，

-系统不可用
-有益的记忆区域全部丢失

我想不出为什么我会选择冷备份，除非出于某种原因它是强制性的。