Marco Pachaly-Mischke 10:16 am on December 22, 2016
Tags: , ,   

RMAN delete obsolete but keep archivelogs

When doing RMAN backups we typically have one strategy and one policy. But the deletion policy always considers not only backups and copies but also archivelogs. In some cases one might want to keep archivelogs for a longer period of time, for instance if you are running a non-Dataguard Standby database using DBVisit. Let’s say we want to keep two generations of backups, we would do the following:

RMAN> CONFIGURE RETENTION POLICY TO REDUNDANCY 2;

new RMAN configuration parameters:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
new RMAN configuration parameters are successfully stored

Now let’s see what backups we have:

RMAN> list backup of database summary;


List of Backups
===============
Key     TY LV S Device Type Completion Time     #Pieces #Copies Compressed Tag
------- -- -- - ----------- ------------------- ------- ------- ---------- ---
23      B  F  A DISK        22.12.2016 09:19:14 1       1       NO         TAG20161222T091750
27      B  F  A DISK        22.12.2016 10:02:33 1       1       NO         TAG20161222T100145
28      B  F  A DISK        22.12.2016 10:02:57 1       1       NO         TAG20161222T100145
29      B  F  A DISK        22.12.2016 10:03:22 1       1       NO         TAG20161222T100145
33      B  F  A DISK        22.12.2016 10:17:14 1       1       NO         TAG20161222T101632
34      B  F  A DISK        22.12.2016 10:17:32 1       1       NO         TAG20161222T101632
35      B  F  A DISK        22.12.2016 10:18:00 1       1       NO         TAG20161222T101632


RMAN> list backup of archivelog all summary;


List of Backups
===============
Key     TY LV S Device Type Completion Time     #Pieces #Copies Compressed Tag
------- -- -- - ----------- ------------------- ------- ------- ---------- ---
24      B  A  A DISK        22.12.2016 09:19:30 1       1       NO         TAG20161222T091930
26      B  A  A DISK        22.12.2016 10:01:34 1       1       NO         TAG20161222T100127
30      B  A  A DISK        22.12.2016 10:03:35 1       1       NO         TAG20161222T100335
32      B  A  A DISK        22.12.2016 10:16:24 1       1       NO         TAG20161222T101615
36      B  A  A DISK        22.12.2016 10:18:16 1       1       NO         TAG20161222T101815

So we have two database backups and corresponding backups of archivelogs. And what archivelogs are still on disk?

RMAN> list archivelog all;

List of Archived Log Copies for database with db_unique_name OLTP
=====================================================================

Key     Thrd Seq     S Low Time
------- ---- ------- - -------------------
46      1    15      A 21.12.2016 12:56:40
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc

41      1    16      A 22.12.2016 09:17:31
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_16_d5q709x1_.arc

43      1    17      A 22.12.2016 09:19:29
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_17_d5q709oq_.arc

35      1    18      A 22.12.2016 10:01:26
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_18_d5q5q65p_.arc

36      1    19      A 22.12.2016 10:03:33
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_19_d5q6gtmj_.arc

38      1    20      A 22.12.2016 10:16:10
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_20_d5q6lm3q_.arc

45      2    11      A 21.12.2016 12:56:30
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc

42      2    12      A 22.12.2016 09:17:20
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_12_d5q709xo_.arc

44      2    13      A 22.12.2016 09:19:14
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_13_d5q709ln_.arc

40      2    14      A 22.12.2016 10:01:12
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_14_d5q709pq_.arc

37      2    15      A 22.12.2016 10:03:18
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_15_d5q6gg9k_.arc

39      2    16      A 22.12.2016 10:15:58
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_16_d5q6l6jm_.arc

That’s all archivelogs that would be needed for recovery of the older database backup. Now let’s see what is obsolete:

RMAN> report obsolete;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
Report of obsolete backups and copies
Type                 Key    Completion Time    Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set           23     22.12.2016 09:19:16
  Backup Piece       23     22.12.2016 09:19:16 /u01/app/oracle/fra/OLTP/43C6AA13C2390666E0538D24100A09EF/backupset/2016_12_22/o1_mf_nnndf_TAG20161222T091750_d5q33orv_.bkp
Backup Set           24     22.12.2016 09:19:30
  Backup Piece       24     22.12.2016 09:19:30 /u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T091930_d5q34ljw_.bkp
Backup Set           25     22.12.2016 09:19:34
  Backup Piece       25     22.12.2016 09:19:34 /u01/app/oracle/fra/OLTP/autobackup/2016_12_22/o1_mf_s_931252772_d5q34ol5_.bkp
Backup Set           26     22.12.2016 10:01:36
  Backup Piece       26     22.12.2016 10:01:36 /u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T100127_d5q5m88s_.bkp
Archive Log          43     22.12.2016 10:25:30 /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_17_d5q709oq_.arc
Archive Log          41     22.12.2016 10:25:30 /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_16_d5q709x1_.arc
Archive Log          42     22.12.2016 10:25:30 /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_12_d5q709xo_.arc
Archive Log          44     22.12.2016 10:25:31 /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_13_d5q709ln_.arc
Archive Log          45     22.12.2016 10:25:35 /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc
Archive Log          46     22.12.2016 10:25:37 /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc

The oldest backup is obsolete which is fine since we already have three full backups. Also all the archivelogs are obsolete since they were already backuped up and can be restored from those backups in case of emergency. But what can we do if we want to keep the archivelogs on disk as long as possible? A “delete obsolete” would remove them along with the outdated database backup.
Let’s try to keep them using “change”:

RMAN> change archivelog all keep until time 'sysdate+3';

released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=279 instance=oltp_1 device type=DISK
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of KEEP command at 12/22/2016 10:29:34
RMAN-06529: CHANGE ... KEEP not supported for ARCHIVELOG

So that is not an option. Maybe changing them to “unavailable” might do the job?

RMAN> change archivelog all unavailable;

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of unavailable command on ORA_DISK_1 channel at 12/22/2016 10:30:43
ORA-19813: cannot have unavailable file /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc in DB_RECOVERY_FILE_DEST

It is not possible to mark archivelog files in FRA as unavailable. There must be another way to excempt the archivelogs from the retention policy. The policy applies to all files known to the database. So let’s get rid of the archivelogs:

RMAN> change archivelog all uncatalog;

uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc RECID=46 STAMP=931256737
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_16_d5q709x1_.arc RECID=41 STAMP=931256730
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_17_d5q709oq_.arc RECID=43 STAMP=931256730
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_18_d5q5q65p_.arc RECID=35 STAMP=931255414
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_19_d5q6gtmj_.arc RECID=36 STAMP=931256170
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_20_d5q6lm3q_.arc RECID=38 STAMP=931256291
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc RECID=45 STAMP=931256735
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_12_d5q709xo_.arc RECID=42 STAMP=931256730
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_13_d5q709ln_.arc RECID=44 STAMP=931256731
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_14_d5q709pq_.arc RECID=40 STAMP=931256729
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_15_d5q6gg9k_.arc RECID=37 STAMP=931256158
uncataloged archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_16_d5q6l6jm_.arc RECID=39 STAMP=931256278
Uncataloged 12 objects

That worked. The files are still there but the database does not know that anymore. Now we can apply the policy in the way we want it:

RMAN> report obsolete;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
Report of obsolete backups and copies
Type                 Key    Completion Time    Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set           23     22.12.2016 09:19:16
  Backup Piece       23     22.12.2016 09:19:16 /u01/app/oracle/fra/OLTP/43C6AA13C2390666E0538D24100A09EF/backupset/2016_12_22/o1_mf_nnndf_TAG20161222T091750_d5q33orv_.bkp
Backup Set           24     22.12.2016 09:19:30
  Backup Piece       24     22.12.2016 09:19:30 /u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T091930_d5q34ljw_.bkp
Backup Set           25     22.12.2016 09:19:34
  Backup Piece       25     22.12.2016 09:19:34 /u01/app/oracle/fra/OLTP/autobackup/2016_12_22/o1_mf_s_931252772_d5q34ol5_.bkp
Backup Set           26     22.12.2016 10:01:36
  Backup Piece       26     22.12.2016 10:01:36 /u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T100127_d5q5m88s_.bkp

The oldest backup is still obsolete, but now archivelogs anymore. That’s want we wannted to achieve. I can now remove the old backup:

RMAN> delete noprompt obsolete;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
using channel ORA_DISK_1
Deleting the following obsolete backups and copies:
Type                 Key    Completion Time    Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set           23     22.12.2016 09:19:16
  Backup Piece       23     22.12.2016 09:19:16 /u01/app/oracle/fra/OLTP/43C6AA13C2390666E0538D24100A09EF/backupset/2016_12_22/o1_mf_nnndf_TAG20161222T091750_d5q33orv_.bkp
Backup Set           24     22.12.2016 09:19:30
  Backup Piece       24     22.12.2016 09:19:30 /u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T091930_d5q34ljw_.bkp
Backup Set           25     22.12.2016 09:19:34
  Backup Piece       25     22.12.2016 09:19:34 /u01/app/oracle/fra/OLTP/autobackup/2016_12_22/o1_mf_s_931252772_d5q34ol5_.bkp
Backup Set           26     22.12.2016 10:01:36
  Backup Piece       26     22.12.2016 10:01:36 /u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T100127_d5q5m88s_.bkp
deleted backup piece
backup piece handle=/u01/app/oracle/fra/OLTP/43C6AA13C2390666E0538D24100A09EF/backupset/2016_12_22/o1_mf_nnndf_TAG20161222T091750_d5q33orv_.bkp RECID=23 STAMP=931252741
deleted backup piece
backup piece handle=/u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T091930_d5q34ljw_.bkp RECID=24 STAMP=931252770
deleted backup piece
backup piece handle=/u01/app/oracle/fra/OLTP/autobackup/2016_12_22/o1_mf_s_931252772_d5q34ol5_.bkp RECID=25 STAMP=931252773
deleted backup piece
backup piece handle=/u01/app/oracle/fra/OLTP/backupset/2016_12_22/o1_mf_annnn_TAG20161222T100127_d5q5m88s_.bkp RECID=26 STAMP=931255288
Deleted 4 objects

Afterwards I can re-register the archivelogs.

RMAN> catalog recovery area noprompt;

searching for all files in the recovery area

List of Files Unknown to the Database
=====================================
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_20_d5q6lm3q_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_16_d5q6l6jm_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_13_d5q709ln_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_17_d5q709oq_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_14_d5q709pq_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_18_d5q5q65p_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_19_d5q6gtmj_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_15_d5q6gg9k_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_16_d5q709x1_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_12_d5q709xo_.arc
cataloging files...
cataloging done

List of Cataloged Files
=======================
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_20_d5q6lm3q_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_16_d5q6l6jm_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_13_d5q709ln_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_17_d5q709oq_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_14_d5q709pq_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_18_d5q5q65p_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_19_d5q6gtmj_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_15_d5q6gg9k_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_16_d5q709x1_.arc
File Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_12_d5q709xo_.arc

The archivelog files are back in the database catalog. Now I can handle them separately and apply any rule I want.

RMAN> delete noprompt archivelog until time 'sysdate-1/12';

released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=279 instance=oltp_1 device type=DISK
List of Archived Log Copies for database with db_unique_name OLTP
=====================================================================

Key     Thrd Seq     S Low Time
------- ---- ------- - -------------------
49      1    15      A 21.12.2016 12:56:40
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc

50      2    11      A 21.12.2016 12:56:30
        Name: /u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc

deleted archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_1_15_d5q709b5_.arc RECID=49 STAMP=931257331
deleted archived log
archived log file name=/u01/app/oracle/fra/OLTP/archivelog/2016_12_22/o1_mf_2_11_d5q709gs_.arc RECID=50 STAMP=931257331
Deleted 2 objects

Not very straight forward, but it does the job.

Inspired by a comment on Twitter by Franck Pachot, the best way to keep a history of archivelogs is not to use “ALL” but “FROM”. So the approach the keep a history of three days would be the follwing:

RMAN> change archivelog from time 'sysdate-3' uncatalog;
RMAN> delete noprompt obsolete;
RMAN> catalog recovery area noprompt;

That way all archivelogs from the last three days are uncataloged. All other archivelogs are handled by the “delete obsolete” operation and there is no need to remove archivelogs manually.