How is the space pressure managed in the Flash Recovery Area - An Example. (文档 ID 315098.1)
In this Document
| Purpose |
| Scope |
| Details |
How is the space pressure managed in the Flash Recovery Area - Example. |
| References |
APPLIES TO:
Oracle Database - Enterprise Edition - Version 9.0.1.0 to 11.2.0.3 [Release 9.0.1 to 11.2]Information in this document applies to any platform.
**Checked for relevance on 26-Mar-2012***
PURPOSE
This article explains the handling of space pressure in Flash Recovery Area
by way of an example.
SCOPE
Oracle DBA's
DETAILS
How is the space pressure managed in the Flash Recovery Area - Example.
Space in the fast recovery area is balanced among backups and archived logs that must be kept
according to the retention policy, and other files that may be subject to deletion. Oracle Database
does not delete eligible files from the fast recovery area until the space must be reclaimed for
some other purpose. Files recently moved to tape are often still available on disk for use in recovery.
The recovery area can thus serve as a cache for tape. When the fast recovery area is full,
Oracle Database automatically deletes eligible files to reclaim space in the recovery area as needed.
This note/example below describes actions which can be done if for any reason FRA runs out of space
because automatic deletion of files is not possible, due to retention policy or other reason etc..
according to the retention policy, and other files that may be subject to deletion. Oracle Database
does not delete eligible files from the fast recovery area until the space must be reclaimed for
some other purpose. Files recently moved to tape are often still available on disk for use in recovery.
The recovery area can thus serve as a cache for tape. When the fast recovery area is full,
Oracle Database automatically deletes eligible files to reclaim space in the recovery area as needed.
This note/example below describes actions which can be done if for any reason FRA runs out of space
because automatic deletion of files is not possible, due to retention policy or other reason etc..
This testcase has been done with the following configuration:
RMAN> show all; using target database controlfile instead of recovery catalog RMAN configuration parameters are: CONFIGURE RETENTION POLICY TO REDUNDANCY 3; CONFIGURE BACKUP OPTIMIZATION OFF; # default CONFIGURE DEFAULT DEVICE TYPE TO DISK; CONFIGURE CONTROLFILE AUTOBACKUP OFF; CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE SBT_TAPE TO '%F'; # default CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default CONFIGURE DEVICE TYPE SBT_TAPE PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # default CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # default CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS 'SBT_LIBRARY=oracle.disksbt,ENV=(BACKUP_DIR=/tmp/)'; CONFIGURE MAXSETSIZE TO UNLIMITED; # default CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/opt/oracle/product/1010/dbs/snapcf_db10g.f'; # default
When the space used in the Flash Recovery Area goes above 85% the we will get
the following warning in the alert log:
Wed Jun 15 21:51:19 2005
Errors in file /opt/oracle/product/1010/admin/db10g/udump/db10g_ora_13900.trc:
ORA-19815: WARNING: db_recovery_file_dest_size of 1073741824 bytes is 86.07% used,
and has 149591552 remaining bytes available.
************************************************************************
You have following choices to free up space from flash recovery area:
1. Consider changing RMAN RETENTION POLICY. If you are using Data Guard,
then consider changing RMAN ARCHIVELOG DELETION POLICY.
2. Back up files to tertiary device such as tape using RMAN
BACKUP RECOVERY AREA command.
3. Add disk space and increase db_recovery_file_dest_size parameter to
reflect the new space.
4. Delete unnecessary files using RMAN DELETE command. If an operating
system command was used to delete files, then use RMAN CROSSCHECK and
DELETE EXPIRED commands.
************************************************************************
When the Flash Recovery Area is completely full then we get a error message as follow:
RMAN-00571: =========================================================== RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: =========================================================== RMAN-03009: failure of backup command on ORA_DISK_1 channel at 06/15/2005 22:39:22 ORA-19809: limit exceeded for recovery files ORA-19804: cannot reclaim 52428800 bytes disk space from 1073741824 limit
To make space reclaimable we have the following options:
1) The space occupied by archivelogs created in the Flash Recovery Area
would become reclaimable in 2 circumstances:
A) If the free space becomes less then 15% in the Flash Recovery Area then all
the archivelogs in the Flash Recovery Area which are not needed for recovery
by the current backups in the FRA will become obsolete and the space occupied
will be shown in the SPACE RECLAIMABLE column of V$RECOVERY_FILE_DEST.
Output BEFORE free space less than 15%:
SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME ------------------------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 913181184 0 11
Output AFTER free space less then 15%:(SPACE_RECLAIMABLE column it is now not zero)
SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME -------------------------------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 913181184 2124288 11 RMAN> report obsolete; RMAN retention policy will be applied to the command RMAN retention policy is set to redundancy 3 Report of obsolete backups and copies Type Key Completion Time Filename/Handle -------------------- ------ ------------------ -------------------- Archive Log 51 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_110_1c0mj1b2_.arc Archive Log 52 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_111_1c0mj8co_.arc Archive Log 53 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_112_1c0mj9tp_.arc Archive Log 54 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_113_1c0mjh6j_.arc Archive Log 55 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_114_1c0mjn90_.arc
B) If the archivelogs have been backed up (either to the Flash Recovery Area itself
or to another destination) and the archivelog not deleted. Then the space occupied
by that archivelog will be marked as reclaimable.
RMAN> backup archivelog all; Starting backup at 15-JUN-05 current log archived using channel ORA_DISK_1 channel ORA_DISK_1: starting archive log backupset channel ORA_DISK_1: specifying archive log(s) in backup set input archive log thread=1 sequence=110 recid=51 stamp=561071961 input archive log thread=1 sequence=111 recid=52 stamp=561071968 input archive log thread=1 sequence=112 recid=53 stamp=561071969 input archive log thread=1 sequence=113 recid=54 stamp=561071975 input archive log thread=1 sequence=114 recid=55 stamp=561071980 input archive log thread=1 sequence=115 recid=56 stamp=561074872 channel ORA_DISK_1: starting piece 1 at 15-JUN-05 channel ORA_DISK_1: finished piece 1 at 15-JUN-05 piece handle=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/backupset/2005_06 _15/o1_mf_annnn_TAG20050615T220755_1c0pc73n_.bkp comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:00:09 Finished backup at 15-JUN-05 RMAN> report obsolete; RMAN retention policy will be applied to the command RMAN retention policy is set to redundancy 3 Report of obsolete backups and copies Type Key Completion Time Filename/Handle -------------------- ------ ------------------ -------------------- Archive Log 51 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_110_1c0mj1b2_.arc Archive Log 52 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_111_1c0mj8co_.arc Archive Log 53 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_112_1c0mj9tp_.arc Archive Log 54 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_113_1c0mjh6j_.arc Archive Log 55 15-JUN-05 /opt/oracle/product/1010/dbs/ora_ flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_114_1c0mjn90_.arc SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME --------------------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 934593024 11767296 13
Here we see that 6 archivelogs have been backed up. Out of the 6 archivelogs
5 are not needed for recovery and are hence obsolete. But 1 of the archivelogs
is needed for recovery and hence is not shown in the report obsolete. But still
the space occupied by that archivelog will be added to the reclaimable space.
2) When the Flash Recovery Area is full and there is no space available to
create archivelogs in the Flash Recovery Area. We will get the following error
in the alert log:
Wed Jun 15 23:01:09 2005 Errors in file /opt/oracle/product/1010/admin/db10g/udump/db10g_ora_13754.trc: ORA-19809: limit exceeded for recovery files ORA-19804: cannot reclaim 1032704 bytes disk space from 1073741824 limit ARCH: Error 19809 Creating archive log file to '/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_116_0_.arc' ARCH: All standby destinations failed; successful archival assumed ARCH: Failed to archive thread 1 sequence 116 (19809) Wed Jun 15 23:01:27 2005 ARC1: Evaluating archive thread 1 sequence 116 ARC1: Archiving not possible: No primary destinations ARC1: Failed to archive thread 1 sequence 116 (4) ARCH: Archival stopped, error occurred. Will continue retrying Wed Jun 15 23:01:27 2005 ORACLE Instance db10g - Archival Error ARCH: Connecting to console port... Wed Jun 15 23:01:27 2005 ORA-16014: log 2 sequence# 116 not archived, no available destinations ORA-00312: online log 2 thread 1: '/opt/oracle/product/1010/oradata/db10g/redo02.log' ARCH: Connecting to console port... ARCH: Wed Jun 15 23:01:27 2005 ORA-16014: log 2 sequence# 116 not archived, no available destinations ORA-00312: online log 2 thread 1: '/opt/oracle/product/1010/oradata/db10g/redo02.log'
3) To free space in the FRA we could do take a backup of the Flash Recovery Area
using the command BACKUP RECOVERY AREA.
This command will take the backup of al the files in the FRA to tape only.
After this the space occupied by the files in the FRA will be marked as reclaimable.
Make sure that you have configured channels for backups to tape for this command to succeed.
RMAN> backup recovery area; Starting backup at 15-JUN-05 released channel: ORA_DISK_1 using channel ORA_SBT_TAPE_1 specification does not match any datafilecopy in the repository channel ORA_SBT_TAPE_1: starting archive log backupset channel ORA_SBT_TAPE_1: specifying archive log(s) in backup set input archive log thread=1 sequence=116 recid=57 stamp=561079349 channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05 channel ORA_SBT_TAPE_1: finished piece 1 at 15-JUN-05 piece handle=28gn2p4a_1_1 comment=API Version 2.0,MMS Version 8.1.3.0 channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:02 input backupset count=58 stamp=561073729 creation_time=15-JUN-05 channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05 piece handle=1qgn2ji1_1_2 comment=API Version 2.0,MMS Version 8.1.3.0 channel ORA_SBT_TAPE_1: finished piece 1 at 15-JUN-05 channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:25 input backupset count=60 stamp=561073791 creation_time=15-JUN-05 channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05 piece handle=1sgn2jjv_1_2 comment=API Version 2.0,MMS Version 8.1.3.0 .... input backupset count=66 stamp=561076762 creation_time=15-JUN-05 channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05 piece handle=22gn2mgq_1_2 comment=API Version 2.0,MMS Version 8.1.3.0 channel ORA_SBT_TAPE_1: finished piece 1 at 15-JUN-05 channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:01 Finished backup at 15-JUN-05
Now the output of the query would look like this:
SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME -------------------------------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 623138304 623138304 7
Note that this command will not delete the files from the FRA. The files would be
deleted whenever any space is required for any new operation.
4) If suppose the FRA is full and the reclaimable space is 0 or insufficient
and we cannot backup the Flash Recovery Area to tape. Then to free
space we may delete unwanted files which are not yet obsolete by the following method:
A) Use the RMAN DELETE command to delete some files from the FRA:
SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME ------------------------------------------------------------------ SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 633155072 0 8 RMAN> delete backupset 45; using channel ORA_DISK_1 using channel ORA_SBT_TAPE_1 List of Backup Pieces BP Key BS Key Pc# Cp# Status Device Type Piece Name ------- ------- --- --- ----------- ----------- ---------- 52 45 1 1 AVAILABLE DISK opt/oracle/product/1010/dbs/ora _flash_area/DB10G/backupset/2005_06_15/o1_mf_ncsnf_TAG20050615T215053_1c0odcbg_.bkp Do you really want to delete the above objects (enter YES or NO)? yes deleted backup piece backup piece handle=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/backupset/ 2005_06_15/o1_mf_ncsnf_TAG20050615T215053_1c0odcbg_.bkp recid=52 stamp=561073891 Deleted 1 objects SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME ------------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 630189568 0 7
B) You can delete the files from the OS using the OS command and then run
the RMAN CROSSCHECK command and DELETE EXPIRED command to free the space.
SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME ------------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 630189568 0 7 [oracle@incq073ac 2005_06_15]$ ls -l total 1016 -rw-r----- 1 oracle dba 1033216 Jun 15 23:22 o1_mf_1_116_1c0tpxb6_.arc [oracle@incq073ac 2005_06_15]$ rm * [oracle@incq073ac 2005_06_15]$ RMAN> crosscheck archivelog all; released channel: ORA_DISK_1 allocated channel: ORA_DISK_1 channel ORA_DISK_1: sid=142 devtype=DISK validation failed for archived log archive log filename=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelo g/2005_06_15/o1_mf_1_116_1c0tpxb6_.arc recid=57 stamp=561079349 validation succeeded for archived log archive log filename=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelo g/2005_06_16/o1_mf_1_117_1c1ds0cf_.arc recid=58 stamp=561097849 Crosschecked 2 objects RMAN> delete expired archivelog all; released channel: ORA_DISK_1 allocated channel: ORA_DISK_1 channel ORA_DISK_1: sid=142 devtype=DISK List of Archived Log Copies Key Thrd Seq S Low Time Name ------- ---- ------- - --------- ---- 57 1 116 X 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB1 0G/archivelog/2005_06_15/o1_mf_1_116_1c0tpxb6_.arc Do you really want to delete the above objects (enter YES or NO)? yes deleted archive log archive log filename=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelo g/2005_06_15/o1_mf_1_116_1c0tpxb6_.arc recid=57 stamp=561079349 Deleted 1 EXPIRED objects SQL> SELECT * FROM V$RECOVERY_FILE_DEST; NAME ---------------------------------------------------------- SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES ----------- ---------- ----------------- --------------- /opt/oracle/product/1010/dbs/ora_flash_area 1073741824 629156864 0 6
Refer Note 829755.1 : Space issue in Flash Recovery Area( FRA )
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