FILE MGMT IN ORACLE.pdf
March 21, 2017 | Author: G.R.THIYAGU ; Oracle DBA | Category: N/A
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ADMINSTRING FILES IN ORACLE
RELOCATE OR RENAME THE DATAFILES USING RMAN We can use RMAN to move datafiles from one location to another location with less time. I am going to move two datafiles from one location to another location. Take rman fresh backup. GETS THE FILE ID , NAME & PATH OF THE FILE
SYS> select file_name, tablespace_name from dba_data_files where tablespace_name='CRMS'; FILE_ID
FILE_NAME
TABLESPACE_NAME
--------- ------------------------ -------------5
/u01/crms/crms02.dbf
CRMS
6
/u01/crms/crms01.dbf
CRMS
RMAN> report schema; Report of database schema for database with db_unique_name CRMS List of Permanent Datafiles =========================== File Size(MB) Tablespace
RB segs Datafile Name
---- -------- -------------------- ------- -----------------------1
870
SYSTEM
***
/u02/app/oracle/oradata/crms/system01.dbf
2
600
SYSAUX
***
/u02/app/oracle/oradata/crms/sysaux01.dbf
3
1730
UNDOTBS1
***
/u02/app/oracle/oradata/crms/undotbs01.dbf
4
487
USERS
***
/u02/app/oracle/oradata/crms/users01.dbf
5
20
CRMS
***
/u01/crms/crms02.dbf
6
50
CRMS
***
/u01/crms/crms01.dbf
7
20
HRMS
***
/u01/app/oracle/oradata/crms/hrms02.dbf
8
50
HRMS
***
/u02/app/oracle/oradata/crms/hrms01.dbf
9
50
TBS1
***
/u02/app/oracle/oradata/crms/tbs01.dbf
10
500
TBS2
***
/u02/app/oracle/oradata/crms/tbs02.dbf
11
500
TBS3
***
/u02/app/oracle/oradata/crms/tbs03.dbf
List of Temporary Files ======================= File Size(MB) Tablespace
Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- -------------------1
20
TEMP
32767
/u02/app/oracle/oradata/crms/temp01.dbf
MAKE THE TABLESPACE TO OFFLINE
RMAN> SQL 'alter tablespace crms offline'; sql statement: alter tablespace crms offline COPY FILE(S) TO THE NEW LOCATION
RMAN> copy datafile 5 to '/u02/app/oracle/oradata/crms/crms01.dbf'; Starting backup at 20-MAY-15 using channel ORA_DISK_1 channel ORA_DISK_1: starting datafile copy
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ADMINSTRING FILES IN ORACLE
input datafile file number=00005 name=/u01/CRMS/crms02.dbf output
file
name=/u02/app/oracle/oradata/crms/crms01.dbf
tag=TAG20150520T150020
RECID=243
STAMP=880210820 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:01 Finished backup at 20-MAY-15
RMAN> copy datafile 6 to '/u02/app/oracle/oradata/crms/crms02.dbf'; Starting backup at 20-MAY-15 using channel ORA_DISK_1 channel ORA_DISK_1: starting datafile copy input datafile file number=00006 name=/u01/CRMS/crms01.dbf output
file
name=/u02/app/oracle/oradata/crms/crms02.dbf
tag=TAG20150520T150025
STAMP=880210826 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:01 Finished backup at 20-MAY-15 USE RMAN ‘SWITCH’ TO THE NEWLY CREATED DATAFILES
RMAN> switch datafile 5 to copy; datafile 5 switched to datafile copy "/u02/app/oracle/oradata/crms/crms01.dbf" RMAN> switch datafile 6 to copy; datafile 6 switched to datafile copy "/u02/app/oracle/oradata/crms/crms02.dbf"
RECOVER THE TABLESPACE
RMAN> recover tablespace crms; Starting recover at 20-MAY-15 using channel ORA_DISK_1 starting media recovery media recovery complete, elapsed time: 00:00:00 Finished recover at 20-MAY-15
TURN THE TABLESPACE TO ONLINE
RMAN> SQL 'alter tablespace crms online'; sql statement: alter tablespace crms online RMAN> report schema; .. ... SYS> select file_name, file_id, tablespace_name from dba_data_files where tablespace_name='CRMS'; FILE_NAME FILE_ID TABLESPACE_NAME ------------------------------------------------ ---------- ------------------/u02/app/oracle/oradata/crms/crms01.dbf 5 CRMS /u02/app/oracle/oradata/crms/crms02.dbf
6
CRMS
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RECID=244
ADMINSTRING FILES IN ORACLE
RELOCATE A SPECIFIC DATAFILE SYS> select file_name, file_id, tablespace_name from dba_data_files where tablespace_name='HRMS'; FILE_NAME
FILE_ID
TABLESPACE_NAME
------------------------------------------------ ---------- ----------------/u02/app/oracle/oradata/crms/hrms02.dbf
7
HRMS
/u01/CRMS/hrms01.dbf
8
HRMS
RMAN> report schema; ... 8 ...
50
HRMS
***
/u01/CRMS/hrms01.dbf
RMAN> SQL 'alter database datafile 8 offline'; sql statement: alter database datafile 8 offline RMAN> copy datafile 8 to '/u02/app/oracle/oradata/crms/hrms01.dbf'; Starting backup at 20-MAY-15 using channel ORA_DISK_1 channel ORA_DISK_1: starting datafile copy input datafile file number=00008 name=/u01/CRMS/hrms01.dbf output
file
name=/u02/app/oracle/oradata/crms/hrms01.dbf
tag=TAG20150520T163717
RECID=258
STAMP=880216638 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:01 Finished backup at 20-MAY-15 RMAN> switch datafile 8 to copy; datafile 8 switched to datafile copy "/u02/app/oracle/oradata/crms/hrms01.dbf"
RMAN> recover datafile 8; Starting recover at 20-MAY-15 using channel ORA_DISK_1 starting media recovery media recovery complete, elapsed time: 00:00:00 Finished recover at 20-MAY-15 RMAN> sql 'alter database datafile 8 online'; sql statement: alter database datafile 8 online
SYS> select file_name, file_id, tablespace_name from dba_data_files where tablespace_name='HRMS'; FILE_NAME
FILE_ID
TABLESPACE_NAME
------------------------------------------------ ---------- -----------------------------/u02/app/oracle/oradata/crms/hrms02.dbf
7
HRMS
/u02/app/oracle/oradata/crms/hrms01.dbf
8
HRMS
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
RELOCATE OR RENAME A DATAFILE USING ALTER TABLESPACE Using alter tablespace command we can rename or relocate a datafile. SYS> select file_id, name, tablespace_name from dba_data_files; SYS> alter database datafile offline; or SYS> alter tablespace offline; Linux> $ mv oldpath/ /new path/ SYS> alter tablespace users RENAME DATAFILE '/old path' TO '/new path' SYS> recover datafile ; or SYS> alter database datafile online; GETS FILE#, NAME & TABLESPACE_NAME
SYS> select file_id, name, tablespace_name from dba_data_files; FILE_ID
FILE_NAME
TABLESPACE_NAME
---------- ------------------------------------------ -----------------4
/u01/crms/datafiles/users01.dbf
USERS
.. ... MAKE THE FILE TO OFFLINE
SYS> alter database datafile 4 offline; Database altered. COPY THE FILE AT OS LEVEL
$ cd /u01/crms/datafiles $ mv users01.dbf
/u02/app/oracle/oradata/crms/users01.dbf
INFORM TO THE DATABASE FILE CHANGED LOCATION
SYS> alter tablespace USERS RENAME DATAFILE '/u01/crms/datafiles/users01.dbf' TO '/u02/app/oracle/oradata/crms/users01.dbf'; Tablespace altered. RECOVER THE FILE & MAKE IT ONLINE
SYS> recover datafile 4; Media recovery complete. SYS> alter database datafile 4 online; Database altered. Using ALTER DATABASE command we can do it. SYS> select file_id, name, tablespace_name from dba_data_files; FILE_ID
FILE_NAME
TABLESPACE_NAME
---------- ------------------------------------------ -----------------9
/u01/crms/datafiles/tbs01.dbf
TBS1
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
SYS> alter database datafile 9 offline; Database altered. $ cd /u01/crms/datafiles $ mv tbs01.dbf
/u02/app/oracle/oradata/crms/tbs01.dbf
SYS> alter database rename file '/u01/crms/datafiles/tbs01.dbf' TO '/u02/app/oracle/oradata/crms/tbs01.dbf'; Tablespace altered. SYS> recover datafile 9; Media recovery complete. SYS> alter database datafile 9 online; Database altered. MULTIPLEXING CONTROL FILES USING SPFILE
SYS> show parameter spfile; NAME
TYPE
VALUE
------------------------------------ ----------- -----------------------------spfile
string
/u02/app/oracle/product/11.2.0 /dbhome_1/dbs/spfilecrms.ora
SYS> show parameter control_file; NAME
TYPE
VALUE
------------------------------------ ----------- -----------------------------control_file_record_keep_time
integer
7
control_files
string
/u02/app/oracle/oradata/crms/c ontrol01.ctl, /u02/app/oracle/ flash_recovery_area/crms/control02.ctl
As you see currently we have only two control files. In order to add a control we need to update the CONTROL_FILES parameter with the new location using the ALTER SYSTEM SET CONTROL_FILES command. SYS> alter system set control_files='/u02/app/oracle/oradata/crms/ctrl/control01.ctl', '/u01/app/oracle/flash_recovery_area/mltplx/crms/ctrl/control02.ctl', '/u03/app/oracle/flash_recovery_area/mltplx/crms/ctrl/control03.ctl' scope=spfile; System altered. Next we have to shutdown the database and copy one of the existing control files to the newly added location as per above alter system command. SHUTDOWN YOUR DATABASE
SYS> shut immediate; Database closed. Database dismounted. ORACLE instance shut down.
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ADMINSTRING FILES IN ORACLE
$ cd /u02/app/oracle/oradata/crms/ $ cp control01.ctl /u02/app/oracle/oradata/crms/ctrl/control01.ctl $ cd /u02/app/oracle/flash_recovery_area/crms/ $ cp control02.ctl /u01/app/oracle/flash_recovery_area/mltplx/ctrl/control02.ctl $ cp control02.ctl /u03/app/oracle/flash_recovery_area/mltplx/ctrl/control03.ctl BRINGUP THE DATABASE
SYS> startup; ORACLE instance started. Total System Global Area 1255473152 bytes Fixed Size
1336232 bytes
Variable Size
989858904 bytes
Database Buffers
251658240 bytes
Redo Buffers
12619776 bytes
Database mounted. Database opened. SYS> select name from v$controlfile; NAME -------------------------------------------------------------------------------/u02/app/oracle/oradata/crms/ctrl/control01.ctl /u01/app/oracle/flash_recovery_area/mltplx/crms/ctrl/control02.ctl /u03/app/oracle/flash_recovery_area/mltplx/crms/ctrl/control03.ctl Multiplexing the control files is a simple process that provides great benefits in the case of control file corruption and loss. MULTIPLEXING CONTROL FILES USING PFILE QUERY TO FIND INITIALIZATION PARAMETER FILE
SYS> show parameter pfile; NAME
TYPE
VALUE
------------------------------------ ----------- -----------------------------spfile
string
SQL> show parameter control_files; NAME
TYPE
VALUE
------------------------------------ ----------- -----------------------------control_files
string
/u01/app/oracle/oradata/devdb/control01.ctl
This database is using single control file. Running database with single control file is not a good choice. So I am going to add two control files. Having multiple control files reduces the risk of control file loss due to corruption or removal.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
SHUTDOWN THE DATABASE
SQL> shut immediate; Database closed. Database dismounted. ORACLE instance shut down.
[oracle@SERVER1 dbs]$ cd $ORACLE_HOME/dbs [oracle@SERVER1 dbs]$ vi initdevdb.ora .. ... control_files=("/u01/app/oracle/oradata/devdb/ctrl/control01.ctl" "/u02/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control02.ctl", "/u03/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control03.ctl") ... COPY & RENAME COTROLFILES AS PER PFILE
$ cd /u01/app/oracle/oradata/devdb $ cp control01.ctl /u01/app/oracle/oradata/devdb/ctrl/control01.ctl $ cp control01.ctl /u02/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control02.ctl $ cp control01.ctl /u03/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control03.ctl MOUNT THE DATABASE USING PFILE
SQL> startup ORACLE instance started. Total System Global Area Fixed Size
901775360 bytes 1276812 bytes
Variable Size
226493556 bytes
Database Buffers
671088640 bytes
Redo Buffers
2916352 bytes
Database mounted. CREATE THE NEW SPFILE
SQL> create spfile from pfile; File created. SQL> shut immediate; ORACLE instance shut down. SQL> startup; ORACLE instance started. .. ... When an instance is started, memory structure of the instance are established by parameters specified within the initialization parameter file. This parameter file can be either pfile or spfile. But priority always goes to spfile. This is a binary file maintained by the server and it can be backed up by RMAN. RMAN cannot backup pfile because it is text file.
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ADMINSTRING FILES IN ORACLE
SQL> show parameter pfile; NAME
TYPE
VALUE
------------------ ----------- -----------------------------spfile
string
/u01/app/oracle/product/10.2.0/db_1/dbs/spfiledevdb.ora
SQL> select name from v$controlfile; NAME -------------------------------------------------------------------------------/u01/app/oracle/oradata/devdb/ctrl/control01.ctl /u02/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control02.ctl /u03/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control03.ctl
CONTROL FILE BACKUP Whenever the database is altered, the control file should be backed up. The primary method of backing up the controlfile is to use a SQL statement to generate a binary file. A binary backup is preferable because it contains additional info such as archived log history , offline tablespaces and backupsets info (for rman backup). BACKUP CONTROL FILE IN BINARY FORMAT
This command is to create a duplicate copy of the existing control file in a specified location. SQL> alter database backup controlfile to '/home/oracle/ctrl.sql'; BACKUP CONTROL FILE IN READABLE FORMAT
Following command produces the SQL script that we can use to recreate the database controlfile in case all multiplexed binary versions of the controlfiles are lost. SQL> alter database backup controlfile to trace; SQL> alter database backup controlfile to trace as '/home/oracle/ctrl.trc'; If you do not mention any location, trace file will be located in UDUMP --> user_dump_dest. To find user_dump_dest location we can use following query in 10g. SQL> show parameter user_dump_dest; In 11g, a new parameter called "diagnostic_dest" determines where files will are created. This diagnostic_dest replaces background_dump_dest, user_dump_dest, core_dump_dest. SQL> show parameter diag; In certain circumstances, we have to recreate our database controlfile. Let’s see. All copies of control files are LOST or CORRUPTED. If we want to change MAX parameter of the database that was set when the database was created. Hard limit parameters are MAXDATAFILES , MAXLOGFILES, MAXLOGHISTORY , etc.. If we move our database to another server which is running the same Operating System but files are present in different location.
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ADMINSTRING FILES IN ORACLE
PRESENT LOCATION OF CONTROLFILES
SYS> select name from v$controlfile; NAME -------------------------------------------------------------------------------/u01/app/oracle/oradata/devdb/ctrl/control01.ctl /u02/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control02.ctl /u03/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control03.ctl SQL> archive log list; Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
6
Next log sequence to archive
8
Current log sequence
8
SQL> column member format a40; SQL> select a.group#, a.member,b.status from v$logfile a, v$log b where a.group#=b.group#; GROUP#
MEMBER
STATUS
---------- ------------------------------------------------- ---------------3
/u01/app/oracle/oradata/devdb/redo03.log
ACTIVE
2
/u01/app/oracle/oradata/devdb/redo02.log
CURRENT
1
/u01/app/oracle/oradata/devdb/redo01.log
ACTIVE
CREATE CONTROL FILE BACKUP USING ANYONE METHOD
File will be created under $ORACLE_HOME/dbs location. SQL> alter database backup controlfile to trace as 'ctrl.txt'; File will be created specified location. SQL> alter database backup controlfile to traces as '/home/oracle/ctrl.sql' Database altered. Edit the trace file just given below. Do not leave any line empty in control file script otherwise it will throw error. Remove all #commented lines. File should looks like given below.
CREATE CONTROLFILE REUSE DATABASE "DEVDB" RESETLOGS
ARCHIVELOG
MAXLOGFILES 16 MAXLOGMEMBERS 3 MAXDATAFILES 100 MAXINSTANCES 8 MAXLOGHISTORY 292 LOGFILE GROUP 1 '/u01/app/oracle/oradata/devdb/redo01.log'
SIZE 50M,
GROUP 2 '/u01/app/oracle/oradata/devdb/redo02.log'
SIZE 50M,
GROUP 3 '/u01/app/oracle/oradata/devdb/redo03.log'
SIZE 50M
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
DATAFILE '/u01/app/oracle/oradata/devdb/system01.dbf', '/u01/app/oracle/oradata/devdb/undotbs01.dbf', '/u01/app/oracle/oradata/devdb/sysaux01.dbf', '/u01/app/oracle/oradata/devdb/users01.dbf', '/u01/app/oracle/oradata/devdb/example01.dbf' CHARACTER SET WE8ISO8859P1 ; RENAMED CONTROL FILE NAMES AT OS LEVEL
$ cd /u01/app/oracle/oradata/devdb/ctrl $ mv control01.ctl control01.ctl.bkp $ cd /u02/app/oracle/fash_recovery_area/mltplx/devdb/ctrl $ mv control02.ctl control02.ctl.bkp $ cd /u03/app/oracle/fash_recovery_area/mltplx/devdb/ctrl $ mv control03.ctl control03.ctl.bkp I have renamed all control files name with .bkp extension.
Generally, whatever you are doing at
operating system level such as (removing database file(s), renaming database files) database cannot understand.
Now we don’t have any control files. Let’s us connect to the database.
SQL> disc Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> conn / as sysdba Connected. SQL> archive log list; ORA-00210: cannot open the specified control file ORA-00202: control file: '/u01/app/oracle/oradata/devdb/ctrl/control01.ctl' ORA-27041: unable to open file Linux Error: 2: No such file or directory Additional information: 3 SHUT THE DATABASE & STARTUP
SQL> shut abort; ORACLE instance shut down. SQL> startup; ORACLE instance started. Total System Global Area Fixed Size
901775360 bytes 1276812 bytes
Variable Size
226493556 bytes
Database Buffers
671088640 bytes
Redo Buffers
2916352 bytes
ORA-00205: error in identifying control file, check alert log for more info
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
Now we have the only one option need to recreate control files from the ctrl.sql file. Let’s try. SQL> select status from v$instance; STATUS -------STARTED SQL> @/home/oracle/ctrl.sql; Control file created. SQL> select status from v$instance; STATUS -----------MOUNTED SQL> select open_resetlogs from v$database; OPEN_RESETL ----------REQUIRED
SQL> alter database open resetlogs; alter database open resetlogs * ERROR at line 1: ORA-01194: file 1 needs more recovery to be consistent ORA-01110: data file 1: '/u01/app/oracle/oradata/devdb/system01.dbf'
SQL> recover database using backup controlfile until cancel; ORA-00279: change 418149 generated at 05/21/2015 20:29:18 needed for thread 1 ORA-00289: suggestion : /u01/app/oracle/flash_recovery_area/DEVDB/archivelog/2015_05_21/o1_mf_1_8_%u_.arc ORA-00280: change 418149 for thread 1 is in sequence #8 Specify log: {=suggested | filename | AUTO | CANCEL} auto ORA-00308: cannot open archived log '/u01/app/oracle/flash_recovery_area/DEVDB/archivelog/2015_05_21/o1_mf_1_8_%u_.arc' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory Additional information: 3 ORA-00308: cannot open archived log '/u01/app/oracle/flash_recovery_area/DEVDB/archivelog/2015_05_21/o1_mf_1_8_%u_.arc' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory Additional information: 3 ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below ORA-01194: file 1 needs more recovery to be consistent ORA-01110: data file 1: '/u01/app/oracle/oradata/devdb/system01.dbf'
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
SQL> select a.group#,a.member,b.status from v$logfile a, v$log b where a.group#=b.group#; GROUP#
MEMBER
STATUS
--------- --------------------------------------------- ---------------------1
/u01/app/oracle/oradata/devdb/redo01.log
ACTIVE
2
/u01/app/oracle/oradata/devdb/redo02.log
ACTIVE
3
/u01/app/oracle/oradata/devdb/redo03.log
CURRENT
SQL> recover database using backup controlfile until cancel; ORA-00279: change 418149 generated at 05/21/2015 20:29:18 needed for thread 1 ORA-00289: suggestion : /u01/app/oracle/flash_recovery_area/DEVDB/archivelog/2015_05_21/o1_mf_1_8_%u_.arc ORA-00280: change 418149 for thread 1 is in sequence #8 Specify log: {=suggested | filename | AUTO | CANCEL} /u01/app/oracle/oradata/devdb/redo03.log ORA-00310: archived log contains sequence 6; sequence 8 required ORA-00334: archived log: '/u01/app/oracle/oradata/devdb/redo03.log' ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below ORA-01194: file 1 needs more recovery to be consistent ORA-01110: data file 1: '/u01/app/oracle/oradata/devdb/system01.dbf' SQL> recover database using backup controlfile until cancel; ORA-00279: change 418149 generated at 05/21/2015 20:29:18 needed for thread 1 ORA-00289: suggestion : /u01/app/oracle/flash_recovery_area/DEVDB/archivelog/2015_05_21/o1_mf_1_8_%u_.arc ORA-00280: change 418149 for thread 1 is in sequence #8 Specify log: {=suggested | filename | AUTO | CANCEL} /u01/app/oracle/oradata/devdb/redo02.log Log applied. Media recovery complete. SQL> alter database open resetlogs; Database altered. SQL> archive log list; Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
1
Next log sequence to archive
1
Current log sequence
1
SQL> select name from v$controlfile; NAME -------------------------------------------------------------------------------/u01/app/oracle/oradata/devdb/ctrl/control01.ctl /u02/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control02.ctl /u03/app/oracle/flash_recovery_area/mltplx/devdb/ctrl/control03.ctl
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
RESETLOGS SQL> alter database open resetlogs; This statement determines the database resets the current redolog sequence number to 1. Whenever you perform incomplete media recovery (can’t use current redolog) or media recovery using a backup controlfile, above SQL statement is really required. Online redologs sequence will be 1. OPEN RESETLOGS
operation creates a new incarnation because the database requires a new incarnation
to avoid confusion when two different redo streams have the same SCNs , occurred in different time. RESETLOGS DOES
Archives the current online redo logs (if they are accessible). Erases the contents of the online redologs and resets the log sequence number to 1. If the current online redo logs are sequence 1000 and 1001, when you open with RESETLOGS, then the database archives the sequence 1000 and 1001 then resets online redologs to sequence to 1 and 2. Creates the online redo log files if they are NOT exist. Resets the controlfile metadata about online redologs and redo threads. Updates all datafiles, online redo log files and all sub sequent archived redo logs with a new RESETLOGS SCN and TIMESTAMP. RMAN> list incarnation; Whenever you open the database with RESETLOGS option, a database incarnation is created. All previous backups became invalid, so it is important to take a full backup of the database. An incarnation helps to identify redo streams which have the same SCN, but occurred at different points in time. This prevents applying the wrong archive log file from a previous incarnation.
Incarnation 1 of the database starts at SCN 1, and continues through SCN 1000 to SCN 2000. At SCN 2000 in incarnation 1, you perform a point-in-time recovery back to SCN 1000, and open the datbase with a RESETLOGS operation. This creates incarnation 2, which begins at SCN 1000 and contines to SCN
3000.
At
SCN
3000
in
incarnation
2,
you
perform
another
point-in-time
and RESETLOGS operation. This creates incarnation 3, starting at SCN 2000.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
recovery
ADMINSTRING FILES IN ORACLE
NORESETLOGS Oracle uses NORESTLOGS when doing complete recovery (entire redo stream was applied). Oracle can use existing log files. The NORESETLOGS option does not clear the redo log files during startup and the online redo logs to be used for recovery if . ARCHIVELOG | NOARCHIVELOG
If you Specify ARCHIVRLOG, Oracle archives the contents of redolog files instead of overwritten. Archive mode helps to recover all committed transactions in the event of system or disk failure. IT is not recommended to run the database in noarchivelog mode, you are disabling archiving of redo logs. It cannot help from the media failure. Once you omit both clause (Archive & Noarchive) by default oracle chooses noarchivelog mode. REUSE | SET
SET: Use SET DATABASE clause to change name of the database. If you do NOT want to rename the database, you should NOT use the ‘SET DATABASE’ clause in the controlfile statement. REUSE: Specify REUSE to indicate existing controlfile(s) can be reused and overwrite if file(s) contain any information. If you omit this clause you will get error following below. ORA-00202: control file: '/u01/app/oracle/oradata/devdb/control01.ctl' ORA-27038: created file already exists SAMPLE CREATE CONTROL FILE SCRIPT
REDOLOG FILES MANAGEMENT The MAXLOGFILES parameter determines the maximum number of groups of redo log files. The MAXLOGMEMBERS parameter determines the maximum number of members for each group. The max and default value for MAXLOGMEMBERS, MAXLOGFILES is dependent on operating system. When compatibility is set to 10.2.0 or later, you can exceed the limit and the control files expand as needed. Suppose compatibility level is set earlier than 10.2.0 the only way to override the upper limit is recreate the database or it’s control file.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
The Oracle database requires a minimum of two redo log files to guarantee, one is available for writing the other is being archived. LGWR writes to redo log files in circular fashion. When the current redo log file fills, LGWR begins writing to the next available redolog file. When the last available redolog file is filled, LGWR returns to the first redolog file & writes on it. MULTIPLEXING REDOLOG FILES
LOGFILE GROUP 1 '/u01/app/oracle/oradata/devdb/A_LOG1.log' SIZE 50M, GROUP 1 '/u02/app/oracle/devdb/redolog/B_LOG1.log' SIZE 50M, GROUP 2 '/u01/app/oracle/oradata/devdb/A_LOG2.log' SIZE 50M, GROUP 2 '/u02/app/oracle/devdb/redolog/B_LOG2.log' SIZE 50M; A_LOG1 & B_LOG1 are both members of Group 1, A_LOG2, B_LOG2 are both members of Group 2. Each member in a group must be exactly the same size. Each member of a log file group is concurrently active i.e. concurrently written by LGWR - as indicated by the identical log sequence numbers assigned by LGWR. At first LGWR writes concurrently to both A_LOG1 & B_LOG1. Then it writes concurrently to both A_LOG2 and B_LOG2, and so on. LGWR never writes concurrently to members of different groups. (For ex, A_LOG1 and B_LOG2. TO CREATE A NEW REDO LOG - GROUP
SQL> alter database add logfile group 1 '/u01/app/oracle/oradata/devdb/redo1a.log' size 50m; Database altered. SQL> alter database add logfile group 2 '/u01/app/oracle/oradata/devdb/redo2a.log' size 50m; Database altered. SQL> alter database add logfile group 3 '/u01/app/oracle/oradata/devdb/redo3a.log' size 50m; Database altered. SQL> select member from v$logfile; MEMBER ------------------------------------------/u01/app/oracle/oradata/devdb/redo1a.log /u01/app/oracle/oradata/devdb/redo2a.log /u01/app/oracle/oradata/devdb/redo3a.log
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
ADDING A MEMBER IN THE EXISTING GROUP
SQL> alter database add logfile member '/u02/app/oracle/oradata/redolog/devdb/redo1b.log' to group 1; Database altered. SQL> alter database add logfile member '/u03/app/oracle/oradata/redolog/devdb/redo1c.log' to group 1; Database altered. SQL> alter database add logfile member '/u02/app/oracle/oradata/redolog/devdb/redo2b.log' to group 2; Database altered. SQL> alter database add logfile member '/u03/app/oracle/oradata/redolog/devdb/redo2c.log' to group 2; Database altered.
SQL> alter database add logfile member '/u02/app/oracle/oradata/redolog/devdb/redo3b.log' to group 3; Database altered. SQL> alter database add logfile member '/u03/app/oracle/oradata/redolog/devdb/redo3c.log' to group 3; Database altered.
CREATE REDOLOG GROUP WITH MULTIPLE MEMBERS
SQL> alter database add logfile group 4 ('/u01/app/oracle/oradata/devdb/redo4a.log', '/u02/app/oracle/oradata/redolog/devdb/redo4b.log', '/u03/app/oracle/oradata/redolog/devdb/redo4c.log') size 50m; Database altered. DROP A MEMBER FROM A REDOLOG GROUP
SQL> alter database drop logfile member '/u03/app/oracle/oradata/redolog/devdb/redo4c.log'; Database altered. SQL> alter database drop logfile member '/u02/app/oracle/oradata/redolog/devdb/redo4b.log'; Database altered. SQL> alter database drop logfile member '/u02/app/oracle/oradata/redolog/devdb/redo4a.log'; alter database drop logfile member '/u03/app/oracle/oradata/redolog/devdb/redo4c.log' * ERROR at line 1: ORA-00361: cannot remove last log member /u03/app/oracle/oradata/redolog/devdb/redo4c.log for group 4 If a group contains only one logfile, you cannot drop the member. You need to drop the group.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
DROP A REDOLOG GROUP
SQL> alter database drop logfile group 4; Database altered. RECREATE DROPPED ONLINE REDOLOG GROUP
Now let’s take a look to recreate online redolog groups. If a group contains only one logfile then you cannot drop that member. Once we drop redolog group/member, the operating system file is NOT deleted from disk. In this case I have already deleted group 4, but files are existing at Operating System level. So I am using reuse clause here. SQL> alter database add logfile group 4 ('/u01/app/oracle/oradata/devdb/log4a.log', '/u02/app/oracle/oradata/redolog/devdb/redo4b.log', '/u03/app/oracle/oradata/redolog/devdb/redo4c.log') size 50m reuse; Database altered. You cannot drop a log group with CURRENT status. We can use ALTER SYSTEM command to make other group to current status. Check these parameters (group#, members, status from v$log) view. SQL> alter system switch logfile; You cannot drop a log group with ACTIVE status. We can use ALTER SYSTEM command to resolve it. SQL> alter system checkpoint.
RESIZE THE REDOLOG FILES
We cannot resize the redolog files. We must drop the redolog file and recreate them and also cannot drop the redolog file if its status is current or active. We have to change the status to inactive then only we can drop it.
SQL> select group#, status from v$log; GROUP#
STATUS
----------
----------
1
INACTIVE
2
INACTIVE
3
INACTIVE
4
CURRENT
SQL> alter database drop logfile group 4; alter database drop logfile group 4 * ERROR at line 1: ORA-01623: log 4 is current log for instance devdb (thread 1) - cannot drop ORA-00312: online log 4 thread 1: '/u01/app/oracle/oradata/devdb/log4a.log'
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
ORA-00312: online log 4 thread 1: '/u02/app/oracle/oradata/redolog/devdb/redo4b.log' ORA-00312: online log 4 thread 1: '/u03/app/oracle/oradata/redolog/devdb/redo4c.log' SQL> alter system switch logfile; System altered. SQL> select group#, status from v$log; GROUP# ---------
STATUS -----------
1
INACTIVE
2
INACTIVE
3
CURRENT
4
INACTIVE
SQL> alter database drop logfile group 4; Database altered. If you do not want to delete the files at operating system level, you will get an error when creating the logfiles with an old name. SQL> alter database add logfile group 4 ('/u01/app/oracle/oradata/devdb/log4a.log', '/u02/app/oracle/oradata/redolog/devdb/log4b.log', '/u03/app/oracle/oradata/redolog/devdb/log4c.log') size 100m; Database altered. STATUS FROM V$LOG
A log group can be in one of four status. CURRENT
Current redo log, the redo log is active.
ACTIVE
Log is active, but it is NOT current log. Required for instance recovery.
INACTIVE
Log is no longer needed for instance recovery and can be overwritten.
UNUSED
Redo log just added or just after a RESETLOGS.
STATUS FROM V$LOGFILE
A log file can be in One of four status. INVALID
File is corrupt or missing. - (inaccessible)
STALE
File is never been used.
DELETED
File is no longer used.
VIEWS FOR REDOLOG
V$LOG
Displays the redo file info from the control file
V$LOGFILE
Identifies redo log groups and members and member status.
V$LOG_HISTORY
Contains log history information.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
RELOCATING OR RENAMAMING REDOLOG FILES
You can use operating system commands to relocate redo logs. I am using 11g database environment to relocate redolog files. Let’s start the process. SQL> select group#, member from v$logfile; GROUP# ----------
MEMBER --------------------------------------------------
3
/u02/app/oracle/oradata/crms/redo03.log
2
/u02/app/oracle/oradata/crms/redo02.log
1
/u02/app/oracle/oradata/crms/redo01.log
The redo logs cannot be moved/renamed while the database is online. The database must be in a mount state to move/rename the online redo logs. First shutdown the database and move online redolog files to their new location. SQL> shut immediate; Database closed. Database dismounted. ORACLE instance shut down. $ cd /u02/app/oracle/oradata/crms $ mv redo01.log
/u01/app/oracle/oradata/redolog/crms/redo01.log
$ mv redo02.log
/u02/app/oracle/oradata/redolog/crms/redo02.log
$ mv redo03.log
/u03/app/oracle/oradata/redolog/crms/redo03.log
Next we bring up the database into mount mode and issue ALTER DATABASE RENAME FILE statements to update the data dictionary and control files. SYS> startup mount; ORACLE instance started. .. ... Database mounted. SYS> alter database rename file '/u02/app/oracle/oradata/crms/redo01.log' to '/u01/app/oracle/oradata/redolog/crms/redo01.log'; Database altered. SYS> alter database rename file '/u02/app/oracle/oradata/crms/redo02.log' to '/u02/app/oracle/oradata/redolog/crms/redo02.log'; Database altered.
SYS> alter database rename file '/u02/app/oracle/oradata/crms/redo03.log' to '/u02/app/oracle/oradata/redolog/crms/redo03.log'; Database altered.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
SYS> alter database open resetlogs; Database altered. SYS>select group#, member from v$logfile; GROUP#
MEMBER
---------- -------------------------------------------------3
/u03/app/oracle/oradata/redolog/crms/redo03.log
2
/u02/app/oracle/oradata/redolog/crms/redo02.log
1
/u01/app/oracle/oradata/redolog/crms/redo01.log
REDOLOGS RECOVERY LOSING ONE MEMBER OF AN ONLINE REDOLOG GROUP
SQL> select member from v$logfile where group#=4; MEMBER --------------------------------------------------/u01/app/oracle/oradata/devdb/log4a.log /u02/app/oracle/oradata/redolog/devdb/log4b.log /u03/app/oracle/oradata/redolog/devdb/log4c.log
SQL>! mv
/u03/app/oracle/oradata/redolog/devdb/log4c.log
/u03/app/oracle/oradata/redolog/devdb/log4c.log.bkp SQL> alter system switch logfile; System altered. Error message messages appeared in the alert log. $ tail -f /u01/app/oracle/admin/devdb/bdump/alert_devdb.log Errors in file /u01/app/oracle/admin/devdb/bdump/devdb_lgwr_20362.trc: ORA-00313: open failed for members of log group 4 of thread 1 ORA-00312: online log 4 thread 1: '/u03/app/oracle/oradata/redolog/devdb/log4c.log' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory .. ... ORA-00321: log 4 of thread 1, cannot update log file header
SQL> select group#, member, status from v$logfile where group#=4 order by 1,2; GROUP#
MEMBER
STATUS
---------- -------------------------------------------------- ------4
/u01/app/oracle/oradata/devdb/log4a.log
4
/u02/app/oracle/oradata/redolog/devdb/log4b.log
4
/u03/app/oracle/oradata/redolog/devdb/log4c.log
INVALID
Ensure that the online redolog file is not part of the current online log group.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
ADMINSTRING FILES IN ORACLE
SQL> alter database drop logfile member '/u03/app/oracle/oradata/redolog/devdb/log4c.log '; Database altered. Add a new member to the group. SQL> alter database add logfile member '/u03/app/oracle/oradata/redolog/devdb/log4c.log' to group 4; Database altered.
TRIM LISTENER LOG (KEEP LAST 3 MONTHS) In 10g, the listener.log is $ORACLE_HOME/network/log/listener.log. In 11g, the default location for the listener log file is the "diag" directory,$ORACLE_HOME/diag. Oracle 11g listener has two log files -- one as an XML file and one as a plain-text file (as was in earlier versions) in the trace directory (it was the log directory in earlier versions). PROCEDURES AND COMMAND
LSNRCTL> set log_status off $ cd /u01/app/oracle/diag/tnslsnr/SERVER1/listener/trace/ $ cp listener.log listener_061212.log (according to current date) $ tail -1000 listener.log > new_listener.log $ mv new_listener.log
listener.log
LSNRCTL> set log_status on TRIM ALERT LOG (KEEP LAST 3 MONTHS)
$ mv alert.log
alert_061212.log
$ cp alert.log
alert_061212.log
(according to current date)
In 11g, the "adrci" tool to purge files from the diag dest - (trace files, core dump etc). REMOVE OLD TRACE FILES IN 10G SQL> show parameter background_dump_dest; SQL> show parameter core_dump_dest; SQL> show parameter user_dump_dest; I am removing files 30 days older. $ cd '/location of bdump/’ $ find . -name '*.trc' -mtime +30 -print -exec rm {} \; $ cd '/location of cdump/’ $ find . -name '*.trc' -mtime +30 -print -exec rm {} \; $ cd '/location of udump/’ $ find . -name '*.trc' -mtime +30 -print -exec rm {} \;
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
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