Subject: | How is the space pressure managed in the Flash Recovery Area - An Example. | |||
Note:315098.1 | Type: | BULLETIN | ||
Last Revision Date: | 06-OCT-2005 | Status: | REVIEWED | |
PURPOSE------- This article explains the handling of space pressure in Flash Recovery Area by way of an example. SCOPE & APPLICATION------------------- DBA, Support How is the space pressure managed in the Flash Recovery Area - Example.----------------------------------------------------------------------- This testcase has been done with the following configuration: RMAN> show all; using target database controlfile instead of recovery catalogRMAN configuration parameters are:CONFIGURE RETENTION POLICY TO REDUNDANCY 3;CONFIGURE BACKUP OPTIMIZATION OFF; # defaultCONFIGURE DEFAULT DEVICE TYPE TO DISK;CONFIGURE CONTROLFILE AUTOBACKUP OFF;CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # defaultCONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE SBT_TAPE TO '%F'; # defaultCONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # defaultCONFIGURE DEVICE TYPE SBT_TAPE PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # defaultCONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # defaultCONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # defaultCONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # defaultCONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # defaultCONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS 'SBT_LIBRARY=oracle.disksbt,ENV=(BACKUP_DIR=/tmp/)';CONFIGURE MAXSETSIZE TO UNLIMITED; # defaultCONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # defaultCONFIGURE 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 22:39:22ORA-19809: limit exceeded for recovery filesORA-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 commandRMAN retention policy is set to redundancy 3Report of obsolete backups and copiesType 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_.arcArchive Log 52 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_111_1c0mj8co_.arcArchive Log 53 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_112_1c0mj9tp_.arcArchive Log 54 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_113_1c0mjh6j_.arcArchive 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-05current log archivedusing channel ORA_DISK_1channel ORA_DISK_1: starting archive log backupsetchannel ORA_DISK_1: specifying archive log(s) in backup setinput archive log thread=1 sequence=110 recid=51 stamp=561071961input archive log thread=1 sequence=111 recid=52 stamp=561071968input archive log thread=1 sequence=112 recid=53 stamp=561071969input archive log thread=1 sequence=113 recid=54 stamp=561071975input archive log thread=1 sequence=114 recid=55 stamp=561071980input archive log thread=1 sequence=115 recid=56 stamp=561074872channel ORA_DISK_1: starting piece 1 at 15-JUN-05channel ORA_DISK_1: finished piece 1 at 15-JUN-05piece handle=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/backupset/2005_06_15/o1_mf_annnn_TAG20050615T220755_1c0pc73n_.bkp comment=NONEchannel ORA_DISK_1: backup set complete, elapsed time: 00:00:09Finished backup at 15-JUN-05 RMAN> report obsolete; RMAN retention policy will be applied to the commandRMAN retention policy is set to redundancy 3Report of obsolete backups and copiesType 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_.arcArchive Log 52 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_111_1c0mj8co_.arcArchive Log 53 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_112_1c0mj9tp_.arcArchive Log 54 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_113_1c0mjh6j_.arcArchive 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 archivelogsis 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 2005Errors in file /opt/oracle/product/1010/admin/db10g/udump/db10g_ora_13754.trc:ORA-19809: limit exceeded for recovery filesORA-19804: cannot reclaim 1032704 bytes disk space from 1073741824 limitARCH: 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 assumedARCH: Failed to archive thread 1 sequence 116 (19809)Wed Jun 15 23:01:27 2005ARC1: Evaluating archive thread 1 sequence 116ARC1: Archiving not possible: No primary destinationsARC1: Failed to archive thread 1 sequence 116 (4)ARCH: Archival stopped, error occurred. Will continue retryingWed Jun 15 23:01:27 2005ORACLE Instance db10g - Archival ErrorARCH: Connecting to console port...Wed Jun 15 23:01:27 2005ORA-16014: log 2 sequence# 116 not archived, no available destinationsORA-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 2005ORA-16014: log 2 sequence# 116 not archived, no available destinationsORA-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-05released channel: ORA_DISK_1using channel ORA_SBT_TAPE_1specification does not match any datafilecopy in the repositorychannel ORA_SBT_TAPE_1: starting archive log backupsetchannel ORA_SBT_TAPE_1: specifying archive log(s) in backup setinput archive log thread=1 sequence=116 recid=57 stamp=561079349channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05channel ORA_SBT_TAPE_1: finished piece 1 at 15-JUN-05piece handle=28gn2p4a_1_1 comment=API Version 2.0,MMS Version 8.1.3.0channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:02input backupset count=58 stamp=561073729 creation_time=15-JUN-05channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05piece handle=1qgn2ji1_1_2 comment=API Version 2.0,MMS Version 8.1.3.0channel ORA_SBT_TAPE_1: finished piece 1 at 15-JUN-05channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:25input backupset count=60 stamp=561073791 creation_time=15-JUN-05channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05piece 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-05channel ORA_SBT_TAPE_1: starting piece 1 at 15-JUN-05piece handle=22gn2mgq_1_2 comment=API Version 2.0,MMS Version 8.1.3.0channel ORA_SBT_TAPE_1: finished piece 1 at 15-JUN-05channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:01Finished backup at 15-JUN-05 RMAN> 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_1using channel ORA_SBT_TAPE_1 List of Backup PiecesBP 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)? yesdeleted backup piecebackup piece handle=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/backupset/2005_06_15/o1_mf_ncsnf_TAG20050615T215053_1c0odcbg_.bkp recid=52 stamp=561073891Deleted 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 -ltotal 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_1allocated channel: ORA_DISK_1channel ORA_DISK_1: sid=142 devtype=DISKvalidation failed for archived logarchive log filename=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_116_1c0tpxb6_.arc recid=57 stamp=561079349validation succeeded for archived logarchive log filename=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_16/o1_mf_1_117_1c1ds0cf_.arc recid=58 stamp=561097849Crosschecked 2 objects RMAN> delete expired archivelog all; released channel: ORA_DISK_1allocated channel: ORA_DISK_1channel ORA_DISK_1: sid=142 devtype=DISK List of Archived Log CopiesKey Thrd Seq S Low Time Name------- ---- ------- - --------- ----57 1 116 X 15-JUN-05 /opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_116_1c0tpxb6_.arc Do you really want to delete the above objects (enter YES or NO)? yesdeleted archive logarchive log filename=/opt/oracle/product/1010/dbs/ora_flash_area/DB10G/archivelog/2005_06_15/o1_mf_1_116_1c0tpxb6_.arc recid=57 stamp=561079349Deleted 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 REFERENCE---------- Note 305817.1 FAQ - Flash Recovery Area feature of 10G
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