19 March, 2016

Compression -- 4 : RMAN (BASIC) Compression

BASIC Compression in RMAN is free with the Enterprise Edition. Advanced Compression with a specified algorithm requires the Advanced Compression Option Licence.

RMAN> backup as compressed backupset database root;

Starting backup at 19-MAR-16
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=48 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00003 name=/u01/app/oracle/oradata/ORCL/datafile/o1_mf_sysaux_9fxmvhl3_.dbf
input datafile file number=00001 name=/u01/app/oracle/oradata/ORCL/datafile/o1_mf_system_9fxmx6s1_.dbf
input datafile file number=00004 name=/u01/app/oracle/oradata/ORCL/datafile/o1_mf_undotbs1_9fxn0vgg_.dbf
input datafile file number=00006 name=/u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_9fxn0t8s_.dbf
channel ORA_DISK_1: starting piece 1 at 19-MAR-16
channel ORA_DISK_1: finished piece 1 at 19-MAR-16
piece handle=/u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T081217_cgtjk2ms_.bkp tag=TAG20160319T081217 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:02:16
Finished backup at 19-MAR-16

Starting Control File and SPFILE Autobackup at 19-MAR-16
piece handle=/u01/app/oracle/fast_recovery_area/ORCL/autobackup/2016_03_19/o1_mf_s_906884075_cgtjofh1_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 19-MAR-16

RMAN> list backup;


List of Backup Sets
===================


BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
1       Full    385.78M    DISK        00:02:09     19-MAR-16      
        BP Key: 1   Status: AVAILABLE  Compressed: YES  Tag: TAG20160319T081217
        Piece Name: /u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T081217_cgtjk2ms_.bkp
  List of Datafiles in backup set 1
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  1       Full 3034354    19-MAR-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_system_9fxmx6s1_.dbf
  3       Full 3034354    19-MAR-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_sysaux_9fxmvhl3_.dbf
  4       Full 3034354    19-MAR-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_undotbs1_9fxn0vgg_.dbf
  6       Full 3034354    19-MAR-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_9fxn0t8s_.dbf

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
2       Full    17.20M     DISK        00:00:03     19-MAR-16      
        BP Key: 2   Status: AVAILABLE  Compressed: NO  Tag: TAG20160319T081435
        Piece Name: /u01/app/oracle/fast_recovery_area/ORCL/autobackup/2016_03_19/o1_mf_s_906884075_cgtjofh1_.bkp
  SPFILE Included: Modification time: 19-MAR-16
  SPFILE db_unique_name: ORCL
  Control File Included: Ckp SCN: 3034519      Ckp time: 19-MAR-16

RMAN> 
CDB$ROOT@ORCL> l
  1  select status, command_id, to_char(start_time,'DD-MON HH24:MI') Start_At, to_char(end_time,'DD-MON HH24:MI') End_At,
  2  trunc(input_bytes/1048576) Input_MB, trunc(output_bytes/1048576) Output_MB, input_type
  3  from v$rman_backup_job_details
  4* order by start_time
CDB$ROOT@ORCL> 
CDB$ROOT@ORCL> /

STATUS              COMMAND_ID                 START_AT         END_AT          INPUT_MB  OUTPUT_MB
------------------- ------------------------- ----------------- ------------- ---------- ----------
INPUT_TYPE
-------------
COMPLETED           2016-03-19T08:12:02       19-MAR 08:12      19-MAR 08:14        1807        402
DB FULL


CDB$ROOT@ORCL> 

Compare the INPUT_MB and OUTPUT_MB to see the compression achieved.

Default compression can also be configured with

RMAN> show compression algorithm;

RMAN configuration parameters for database with db_unique_name ORCL are:
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default

RMAN> 
RMAN> CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET;

new RMAN configuration parameters:
CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET PARALLELISM 1;
new RMAN configuration parameters are successfully stored

RMAN> 
RMAN> backup datafile 1;

Starting backup at 19-MAR-16
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/ORCL/datafile/o1_mf_system_9fxmx6s1_.dbf
channel ORA_DISK_1: starting piece 1 at 19-MAR-16
channel ORA_DISK_1: finished piece 1 at 19-MAR-16
piece handle=/u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T082704_cgtkdrdh_.bkp tag=TAG20160319T082704 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:55
Finished backup at 19-MAR-16

Starting Control File and SPFILE Autobackup at 19-MAR-16
piece handle=/u01/app/oracle/fast_recovery_area/ORCL/autobackup/2016_03_19/o1_mf_s_906884879_cgtkgk5d_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 19-MAR-16

RMAN> list backup of datafile 1;


List of Backup Sets
===================


BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
1       Full    385.78M    DISK        00:02:09     19-MAR-16      
        BP Key: 1   Status: AVAILABLE  Compressed: YES  Tag: TAG20160319T081217
        Piece Name: /u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T081217_cgtjk2ms_.bkp
  List of Datafiles in backup set 1
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  1       Full 3034354    19-MAR-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_system_9fxmx6s1_.dbf

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
3       Full    207.82M    DISK        00:00:55     19-MAR-16      
        BP Key: 3   Status: AVAILABLE  Compressed: YES  Tag: TAG20160319T082704
        Piece Name: /u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T082704_cgtkdrdh_.bkp
  List of Datafiles in backup set 3
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  1       Full 3035302    19-MAR-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_system_9fxmx6s1_.dbf

RMAN> 
CDB$ROOT@ORCL> l
  1  select status, command_id, to_char(start_time,'DD-MON HH24:MI') Start_At, to_char(end_time,'DD-MON HH24:MI') End_At,
  2  trunc(input_bytes/1048576) Input_MB, trunc(output_bytes/1048576) Output_MB, input_type
  3  from v$rman_backup_job_details
  4* order by start_time
CDB$ROOT@ORCL> /

STATUS              COMMAND_ID                START_AT          END_AT             INPUT_MB OUTPUT_MB
------------------- ------------------------- ----------------- ----------------- --------- ---------
INPUT_TYPE
-------------
COMPLETED           2016-03-19T08:12:02       19-MAR 08:12      19-MAR 08:14           1807       402
DB FULL

COMPLETED           2016-03-19T08:18:29       19-MAR 08:27      19-MAR 08:28            803       225
DATAFILE FULL


CDB$ROOT@ORCL> 
CDB$ROOT@ORCL> !du -sh /u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T082704_cgtkdrdh_.bkp
208M /u01/app/oracle/fast_recovery_area/ORCL/backupset/2016_03_19/o1_mf_nnndf_TAG20160319T082704_cgtkdrdh_.bkp

CDB$ROOT@ORCL> 


Note the slight discrepancy in reported backuppiece size.  The LIST BACKUP shows it as 207.82MB,  the query on v$rman_backup_job_details dividing the output_bytes by 1048576 shows the size as 225MB (truncating to units) while the OS level "du -sh" command shows it as 208MB.
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