Multisection Backup for Image Copies

A nice Oracle Database 12c New Feature enhances the multisection backup, introduced in 11g: You can use it now for image copies also!

Multisection Backup with Image Copy

Multisection Backup with Image Copy

RMAN> report schema;

using target database control file instead of recovery catalog
Report of database schema for database with db_unique_name PRIMA

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    347      SYSTEM               YES     /u01/app/oracle/oradata/prima/system01.dbf
2    235      SYSAUX               NO      /u01/app/oracle/oradata/prima/sysaux01.dbf
3    241      UNDOTBS1             YES     /u01/app/oracle/oradata/prima/undotbs01.dbf
4    602      USERS                NO      /u01/app/oracle/oradata/prima/users01.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    40       TEMP                 32767       /u01/app/oracle/oradata/prima/temp01.dbt

RMAN> configure device type disk parallelism 2;

new RMAN configuration parameters:
CONFIGURE DEVICE TYPE DISK PARALLELISM 2 BACKUP TYPE TO BACKUPSET;
new RMAN configuration parameters are successfully stored

RMAN> backup section size 301m as copy datafile 4;

Starting backup at 29-JUN-15
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_1: starting datafile copy
input datafile file number=00004 name=/u01/app/oracle/oradata/prima/users01.dbf
backing up blocks 1 through 38528
channel ORA_DISK_2: starting datafile copy
input datafile file number=00004 name=/u01/app/oracle/oradata/prima/users01.dbf
backing up blocks 38529 through 77056
output file name=/u02/fra/PRIMA/datafile/o1_mf_users_bs2v934z_.dbf tag=TAG20150629T180658
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:15
output file name=/u02/fra/PRIMA/datafile/o1_mf_users_bs2v934z_.dbf tag=TAG20150629T180658
channel ORA_DISK_2: datafile copy complete, elapsed time: 00:00:15
Finished backup at 29-JUN-15

RMAN> host 'ls -rtl /u02/fra/PRIMA/datafile/';

total 616468
-rw-r-----. 1 oracle oinstall 631250944 Jun 29 18:07 o1_mf_users_bs2v934z_.dbf
host command complete

We use backupsets by default now especially also upon the DUPLICATE DATABASE command, which leads finally to image copies of course.

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  1. #1 by Mikhail Velikikh on June 30, 2015 - 09:38

    Hi Uwe,

    @ You can use it now for image copies also!

    May be it’s slightly offtopic, but I would like to ask you about usage of section size with cross-platform migration.

    Do you have any information about the SECTION SIZE for XTTS migration?

    I would like to describe the issue that I faced 3 years ago.
    My company decided to migrate multi TB database from HP-UX IA64 to Linux x86-64.
    We are used Oracle 11.2.0.3 version.
    I utilized XTTS to accomplish this task.
    At one of the steps I executed command CONVERT DATAFILE TO PLATFORM on the Linux host.

    Most tablespaces was smallfile with datafile sizes below 32Gb, but one of them was bigfile tablespace with size 300Gb.
    AFAIK CONVERT DATAFILE didn’t support SECTION SIZE parameter.
    To perform migration within allotted downtime window, I had to migrate all data from the bigfile tablespace to the smallfile tablespace first.

    After some time I discovered that Oracle had announced the Cross Platform Incremental backups.
    It could extremely simplify the migration, but our migration was performed without this.

    In the 12.1.0.1 Oracle made an enhancements to the Cross-platform backup and restore.
    As I see in the documentation for BACKUP command:
    http://docs.oracle.com/database/121/RCMRF/rcmsynta006.htm#sthref217
    When you use either the FOR TRANSPORT or TO PLATFORM clause, you cannot use the following clauses of the BACKUP command:
    SECTION SIZE

    So I suppose that CONVERT DATAFILE command still cannot utilize SECTION SIZE.
    It’s a serious restriction for customers that use a bigfile tablespaces.

    Best regards,
    Mikhail.

  2. #2 by Tim on January 8, 2016 - 21:31

    I am wondering about your image. Shouldn’t there be an additional level? I would have thought the channels would have written backup pieces and the backup pieces would be part of one backup set.

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