Skip to Main Content
  • Questions

  • RMAN Full Hot or Cold Backup - which is faster?

Breadcrumb

Question and Answer

Connor McDonald

Thanks for the question, Kel.

Asked: March 09, 2017 - 5:12 am UTC

Last updated: March 11, 2017 - 1:50 am UTC

Version: 11.2.0.4

Viewed 1000+ times

You Asked

Which RMAN backup is faster, full hot or cold?

and Connor said...

They will be about the same, because they both do approximately the same amount of I/O work. The hot backup may consume more CPU, because it may need to do more work with modified blocks, and this would be easy enough for you to test on your platform. For my machine, there's no difference (but of course, its hardly an active database)

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>



but when you consider the drawbacks of a cold backup, ie,

- system unavailable
- beneficial memory areas all lost

I can't think of why I'd ever opt for a cold backup unless it was mandatory for some reason.

Rating

  (2 ratings)

Is this answer out of date? If it is, please let us know via a Comment

Comments

Conclusion

A reader, March 10, 2017 - 7:57 am UTC

It looks to me that your conclusion about cold bkp is somehow contradictory ? ?
Could you please clarify ?


"but when you consider the drawbacks of a cold backup, ie,

- system unavailable
- beneficial memory areas all lost

I can't think of why I'd ever opt for a cold backup unless it was mandatory for some reason. "
Connor McDonald
March 11, 2017 - 1:50 am UTC

Sorry - you've lost me ?


"I can't think of why I'd ever opt for a cold backup"

ie, I dont like cold backups.

Quick and through

Kel Bell, March 10, 2017 - 12:18 pm UTC

Thank you,

Your response was quick and thorough.

Carla
more

Connor and Chris don't just spend all day on AskTOM. You can also catch regular content via Connor's blog and Chris's blog. Or if video is more your thing, check out Connor's latest video and Chris's latest video from their Youtube channels. And of course, keep up to date with AskTOM via the official twitter account.

More to Explore

VLDB

If you are new to partitioning, check out Connor McDonald's introduction series here.

VLDB

Documentation set on VLDB and Partitioning.