Why it automatically recover current redo log in RMAN command window?
Firstly, I restore controlfile and datafiles from a backupset.
Then when I recover database in RMAN command window like below:
RMAN> recover database;
Starting recover at 15-AUG-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=156 devtype=DISK
starting media recovery
archive log thread 1 sequence 9 is already on disk as file /u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_9_90sd0slz_.arc
archive log thread 1 sequence 10 is already on disk as file
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_10_90sd0tsb_.arc
archive log thread 1 sequence 11 is already on disk as file
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_11_90sd110b_.arc
archive log thread 1 sequence 12 is already on disk as file
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_12_90sd2ksr_.arc
archive log thread 1 sequence 13 is already on disk as file
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_13_90sd2mc6_.arc
archive log thread 1 sequence 14 is already on disk as file
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_14_90sd2qrm_.arc
archive log thread 1 sequence 15 is already on disk as file
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_15_90sd2s0w_.arc
archive log thread 1 sequence 16 is already on disk as file /u01/app/oracle/oradata/lonion/redo03.log
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_9_90sd0slz_.arc thread=1 sequence=9
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_10_90sd0tsb_.arc thread=1 sequence=10
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_11_90sd110b_.arc thread=1 sequence=11
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_12_90sd2ksr_.arc thread=1 sequence=12
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_13_90sd2mc6_.arc thread=1 sequence=13
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_14_90sd2qrm_.arc thread=1 sequence=14
archive log filename=/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_15_90sd2s0w_.arc thread=1 sequence=15
archive log filename=/u01/app/oracle/oradata/lonion/redo03.log thread=1 sequence=16
media recovery complete, elapsed time: 00:00:04
Finished recover at 15-AUG-13
RMAN>
But, when I recover database in SQL*Plus command window like below:
[oracle@lonion ~]$ uniread sqlplus /nolog
[uniread] Loaded history (2178 lines)
SQL*Plus: Release 10.2.0.1.0 - Production on Thu Aug 15 19:25:38 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
SQL> conn /as sysdba
Connected.
SQL>
SQL> recover database;
ORA-00283: recovery session canceled due to errors
ORA-01610: recovery using the BACKUP CONTROLFILE option must be done
SQL> recover database using backup controlfile;
ORA-00279: change 2147842454 generated at 08/15/2013 18:34:28 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_9_%u_.a
rc
ORA-00280: change 2147842454 for thread 1 is in sequence #9
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00279: change 2147842651 generated at 08/15/2013 18:40:25 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_10_%u_.
arc
ORA-00280: change 2147842651 for thread 1 is in sequence #10
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_9_90sd
0slz_.arc' no longer needed for this recovery
ORA-00279: change 2147842653 generated at 08/15/2013 18:40:26 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_11_%u_.
arc
ORA-00280: change 2147842653 for thread 1 is in sequence #11
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_10_90s
d0tsb_.arc' no longer needed for this recovery
ORA-00279: change 2147842656 generated at 08/15/2013 18:40:32 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_12_%u_.
arc
ORA-00280: change 2147842656 for thread 1 is in sequence #12
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_11_90s
d110b_.arc' no longer needed for this recovery
ORA-00279: change 2147842684 generated at 08/15/2013 18:41:21 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_13_%u_.
arc
ORA-00280: change 2147842684 for thread 1 is in sequence #13
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_12_90s
d2ksr_.arc' no longer needed for this recovery
ORA-00279: change 2147842686 generated at 08/15/2013 18:41:23 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_14_%u_.
arc
ORA-00280: change 2147842686 for thread 1 is in sequence #14
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_13_90s
d2mc6_.arc' no longer needed for this recovery
ORA-00279: change 2147842689 generated at 08/15/2013 18:41:27 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_15_%u_.
arc
ORA-00280: change 2147842689 for thread 1 is in sequence #15
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_14_90s
d2qrm_.arc' no longer needed for this recovery
ORA-00279: change 2147842691 generated at 08/15/2013 18:41:28 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_16_%u_.
arc
ORA-00280: change 2147842691 for thread 1 is in sequence #16
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_15_90s
g0or9_.arc' no longer needed for this recovery
ORA-00279: change 2147842986 generated at 08/15/2013 19:14:29 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_17_%u_.
arc
ORA-00280: change 2147842986 for thread 1 is in sequence #17
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_16_90s
g0os5_.arc' no longer needed for this recovery
ORA-00308: cannot open archived log
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_17_%u_
.arc'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
SQL> recover database using backup controlfile;
ORA-00279: change 2147842986 generated at 08/15/2013 19:14:29 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_08_15/o1_mf_1_17_%u_.
arc
ORA-00280: change 2147842986 for thread 1 is in sequence #17
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
/u01/app/oracle/oradata/lonion/redo01.log ---- Yon see, proceeding this process, it can't automatically apply the current redo log.
Log applied.
Media recovery complete.
SQL>
Question Coming:
Now, my question is that 「Why it automatically recover current redo log in RMAN command window but not in SQL*Plus」?
BTW: Please pay attention to the red font.
It also seems not work.
SQL> recover automatic database using backup controlfile;
ORA-00279: change 2148632889 generated at 09/26/2013 12:45:22 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_09_26/o1_mf_1_48_%u_.
arc
ORA-00280: change 2148632889 for thread 1 is in sequence #48
ORA-00278: log file
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_09_26/o1_mf_1_48_%u_
.arc' no longer needed for this recovery
ORA-00308: cannot open archived log
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_09_26/o1_mf_1_48_%u_
.arc'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00308: cannot open archived log
'/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_09_26/o1_mf_1_48_%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/LONION/archivelog/2013_09_26/o1_mf_1_48_%u_
.arc'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file
or directory
Additional information: 3
SQL>
It must specify the redo log.
SQL> recover database using backup controlfile;
ORA-00279: change 2148632889 generated at 09/26/2013 12:45:22 needed for thread
1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/LONION/archivelog/2013_09_26/o1_mf_1_48_%u_.
arc
ORA-00280: change 2148632889 for thread 1 is in sequence #48
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
/u01/app/oracle/oradata/lonion/redo02.log
Log applied.
Media recovery complete.
SQL>
Similar Messages
-
Hi All,
I got a scenario in which my current redo log file is lost:
Do I need to:
1)Clear log file group
(or)
2)I should perform incomplete recovery.
What are the steps I should follow to recover this current redo log file?
1)*If it is inactive* I can make use of
ALTER DATABASE CLEAR LOGFILE UNARCHIVED GROUP 2;
which will drop and recreate the log file.To recover from loss of an active online log group in NOARCHIVELOG mode:
If the media failure is temporary, then correct the problem so that the database can reuse the group when required.
Restore the database from a consistent, whole database backup (datafiles and control files) as described in "Restoring Datafiles Before Performing Incomplete Recovery". For example, enter:
% cp /disk2/backup/*.dbf $ORACLE_HOME/oradata/trgt/
Mount the database:
STARTUP MOUNT
Because online redo logs are not backed up, you cannot restore them with the datafiles and control files. In order to allow the database to reset the online redo logs, you must first mimic incomplete recovery:
RECOVER DATABASE UNTIL CANCEL
CANCEL
Open the database using the RESETLOGS option:
ALTER DATABASE OPEN RESETLOGS;
Shut down the database consistently. For example, enter:
SHUTDOWN IMMEDIATE
Make a whole database backup.
To recover from loss of an active online redo log group in ARCHIVELOG mode:
If the media failure is temporary, then correct the problem so that the database can reuse the group when required. If the media failure is not temporary, then use the following procedure.
Begin incomplete media recovery, recovering up through the log before the damaged log.
Ensure that the current name of the lost redo log can be used for a newly created file. If not, then rename the members of the damaged online redo log group to a new location. For example, enter:
ALTER DATABASE RENAME FILE "?/oradata/trgt/redo01.log" TO "/tmp/redo01.log";
ALTER DATABASE RENAME FILE "?/oradata/trgt/redo01.log" TO "/tmp/redo02.log";
Open the database using the RESETLOGS option:
ALTER DATABASE OPEN RESETLOGS;
My question is when the redo log file is current. What steps we should follow?
Best regards,
Rafi.
http://rafioracledba.blogspot.com/
2)If it is active then I can make use of below steps:Rafi (Oracle DBA) wrote:
Hi Asif,
This link I have seen by refering to previous post.I just have a slight doubt in mind.
1)Do I need to make use of statement:
Alter database clear unarchived log file group#;
(or)
Only if your group is current(or you are not able to drop it) and is not archived then you should use above query.
We should perform incomplete recovery for this.If we have to perform incomplete recovery what are the steps I should follow?
I doubt you should be performing incomplete recovery for this.
Eg:Let us say my group 1 is dropped it has only one member and it is in active state.How to recover database?Can I get the steps?
You would not be able to drop it if it is in active state, did you meant it is corrupted? If yes then you can use below query
Alter database clear [unarchived] LOGFILE GROUP #;>
Best regards,
Rafi
http://rafioracledba.blogspot.com/
Make sure to backup your database after above activity.
Regards
Anurag -
I have 6 Tera byte of database. My current redo log is currpted. I dont want to go for incomplete recovery as my database size is too large.
what is the other option to recover the database
oracle version is 9iThis method wont work because I am talking about current online redo log
You can clear an inactive redo log group when the database is open or closed. The procedure depends on whether the damaged group has been archived.
To clear an inactive, online redo log group that has been archived, use the following procedure:
1. If the database is shut down, then start a new instance and mount the database:
STARTUP MOUNT
2. Reinitialize the damaged log group. For example, to clear redo log group 2, issue the following statement:
ALTER DATABASE CLEAR LOGFILE GROUP 2; -
Recovery of online (current) redo-logs
Hello Recovery experts,
My question is related to recovery of online (current) redo-logs group.
1) Is it required to bring down the database for performing recovery of online (current) redo-logs group ?
2) Is below commands sufficient ?
'alter database clear logfile <group num>' ;
'alter database open resetlogs;'
3) Any other suggestions ?
Help appreciated.... cause I dont have a test setup. I tried to do on a windows desktop. and above commands worked fine. (but i think there may be more commands. my database is really not doing anything (idle) hence no redo is really getting generated.It may depend on the true state of the redo log.
Check Recovering After the Loss of Online Redo Log Files: Scenarios and Losing an Active Online Redo Log Group.
To force a redo log switch issue:
SQL> alter system switch logfile; -
Missing current redo log files
hello to all
i have a question please if you can guide me.
if i lose all current redo log files (current redo log group files) how i can repair it and open
database ? (i don't have problem by missing INACTIVE redo group)
thanksHi,
>>if i lose all current redo log files (current redo log group files) how i can repair it and
open database ? (i don't have problem by missing INACTIVE redo group)Well, It depends. The database was active when the current log file was lost ? Are you using RMAN ? The database is operating in ARCHIVELOG mode or NOARCHIVEMOG mode ? Basically, an incomplete recovery is necessary when there is a loss of the current redo log files. It means that you don’t have all the redo log files up to the point of failure, so the only alternative is[b] to recover prior to the point of failure. To perform incomplete recovery after the redo log files have been lost, you do the following (if you are not using RMAN):
1) Execute a SHUTDOWN command and restore all data files (*.dbf) from most recent backup.
2) Execute a STARTUP MOUNT command to read the contents of the control file.
3) Execute a RECOVER DATABASE UNTIL CANCEL command to start the recovery process.
SQL> startup mount;
4) Execute a RECOVER DATABASE UNTIL CANCEL command to start the recovery process.
SQL> recover database until cancel;
5) Apply the necessary archived logs up to, but not including, the lost or corrupted log.
6) Open the database and reset the log files.
SQL> alter database open resetlogs;
7) Shut down the database.
SQL> shutdown normal;
8) Take a full cold backup
In resume, for more information, take a look at [url http://download-west.oracle.com/docs/cd/B19306_01/backup.102/b14191/recoscen008.htm#sthref1872]Recovering After the Loss of Online Redo Log Files: Scenarios
Cheers
Legatti -
Suppose the current online redo log is corrupted, is there any way to make database functional other than doing incomplete recovery?
Oracle documentation says we have to do incomplete recovery. Is Cancel based Incomplete recovery the only option.
If this database is also the primary database for A physical standby database how to synchronize the Standby database with Primary? Since we would be opening Primary with Resetlogs....Incomplete Recovery upto the last (archive) redo log before the current one IS the only option.
Your current redo log would have some transactions in it. Also, the datafiles would have had some dirty blocks written to disk by DBWR. Therefore, the datafiles would be inconsistent until and unless you can apply the redo that goes with those changes. Since the redo cannot be applied from the corrupt file, the datafiles themselves must be reverted to a prior image -- upto the last redo that can be applied.
As for the standby, if you have Flashback configured, you can Flashback the Standby to the point 2 SCNs before the Primary Resetlogs.
See DataGuard Scenario 12.5 at
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/scenarios.htm#i1049616
Else use Scenario 8.4 at
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/manage_ps.htm#i1026480
Hemant K Chitale
http://hemantoracledba.blogspot.com
Edited by: Hemant K Chitale on Jul 22, 2009 12:13 AM -
Need to drop a current redo log on a Standby
Oracle 11.2.0.2
I have 3 redo logs on a newly created Standby database.
SQL> SELECT GROUP#, ARCHIVED, STATUS FROM V$LOG;
GROUP# ARC STATUS
1 YES UNUSED
3 NO CURRENT
2 YES UNUSED
The redo log in Group 3 needs to be dropped and recreated. How can I force a log switch on a Standby in mount mode?
SQL> alter database drop logfile group 3;
alter database drop logfile group 3
ERROR at line 1:
ORA-01623: log 3 is current log for instance ufms216 (thread 1) - cannot drop
ORA-00312: online log 3 thread 1: '/path/redo03.dbf'
SQL> alter system switch logfile;
alter system switch logfile
ERROR at line 1:
ORA-01109: database not open
Please help !!!
Thanks!
DaveSAME ERROR/SITUATION
SQL> startup mount
ORACLE instance started.
Total System Global Area 1.2527E+10 bytes
Fixed Size 2231240 bytes
Variable Size 3657434168 bytes
Database Buffers 8858370048 bytes
Redo Buffers 8691712 bytes
Database mounted.
SQL> SELECT GROUP#, ARCHIVED, STATUS FROM V$LOG;
GROUP# ARC STATUS
1 YES UNUSED
3 NO CURRENT
2 YES UNUSED
SQL> alter database drop logfile group 3;
alter database drop logfile group 3
ERROR at line 1:
ORA-01623: log 3 is current log for instance ufms216 (thread 1) - cannot drop
ORA-00312: online log 3 thread 1: '/a0253/d01/oradata/ufms216/redo03.dbf'
SQL> alter system switch logfile;
alter system switch logfile
ERROR at line 1:
ORA-01109: database not open
SQL> alter database recover managed standby database cancel;
alter database recover managed standby database cancel
ERROR at line 1:
ORA-16136: Managed Standby Recovery not active
SQL>
HELP! -
ORACLE 11.2.0.2
I have a corrupted redo log on a Physical Standby db. The corrupted file is the current log. I cant do an "alter system switch logfile" because the database is not writeable.
SQL> alter database open;
Database altered.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;
Database altered.
SQL> SELECT GROUP#, ARCHIVED, STATUS FROM V$LOG;
GROUP# ARC STATUS
1 YES UNUSED
2 YES UNUSED
3 NO CURRENT
SQL>
SQL> alter system switch logfile;
alter system switch logfile
ERROR at line 1:
ORA-16000: database open for read-only access
How can I drop log file #3? The database is currently a physical, if I convert ti to a logical, then the dp would be writeable. Would this work? Any other ideas??http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/manage_ps.htm
8.3.5 Adding or Dropping Online Redo Log Files
Changing the size and number of the online redo log files is sometimes done to tune the database. You can add or drop online redo log file groups or members to the primary database without affecting the standby database. Similarly, you can drop log file groups or members from the primary database without affecting your standby database. However, these changes do affect the performance of the standby database after switchover.
Caution:
Whenever you add an online redo log file to the primary database, you should add corresponding online and standby redo log files to the standby database.
For example, if the primary database has 10 online redo log files and the standby database has 2, and then you switch over to the standby database so that it functions as the new primary database, the new primary database is forced to archive more frequently than the original primary database.
Consequently, when you add or drop an online redo log file at the primary site, it is important that you synchronize the changes in the standby database by following these steps:
If Redo Apply is running, you must cancel Redo Apply before you can change the log files.
If the STANDBY_FILE_MANAGEMENT initialization parameter is set to AUTO, change the value to MANUAL.
Add or drop an online redo log file:
To add an online redo log file, use a SQL statement such as this:
SQL> ALTER DATABASE ADD LOGFILE '/disk1/oracle/oradata/payroll/prmy3.log' SIZE 100M;
To drop an online redo log file, use a SQL statement such as this:
SQL> ALTER DATABASE DROP LOGFILE '/disk1/oracle/oradata/payroll/prmy3.log';
Repeat the statement you used in Step 3 on each standby database.
Restore the STANDBY_FILE_MANAGEMENT initialization parameter and the Redo Apply options to their original states. -
Why do we need standby redo log on Primary database.
Hi Gurus,
I was going through the document in OBE,
http://www.oracle.com/technology/obe/11gr1_db/ha/dataguard/physstby/physstdby.htm
I have two queries:
1) I noticed the statement -
"Configure the primary database to receive redo data, by adding the standby logfiles to the primary. "
Why do we have to create standby redo log on a primary database?
2) There is another statement --
"It is highly recommended that you have one more standby redo log group than you have online redo log groups as the primary database. The files must be the same size or larger than the primary database’s online redo logs. "
Why do we need one additional standby redo log group than in Primary database.
Could anyone please explain to me in simple words.
Thanks
Cherrish VaidiyanHi,
1. Standby redo logs are used only when the database_role is standby, it is recommended to be added in primary also so that they can be used on role reversal, however during normal working standby redo logs will not be used at all on primary.
2. In case of 3 online redo log groups, it is recommended to use 4 standby redo log group this is in case if log switching is happening frequently on primary and all 3 standby redo logs are still not completely archived on the standby and 4th can be used here as there will be some delay on standby due to network or slowness of arch on standby.
Use of the standby redo log groups depends on the redo generation rate, you can see only 2 standby redo logs are getting used while you have 4 standby redo log groups, when the redo generation rate is less.
So it is recommended to have one more standby redo log group when redo generation rate is high and all of the existing standby redo log group are getting used.
Regards
Anudeep -
Increase current redo log size in standby database in mount stage
We have oracle 10g standby database. The standby database is always running in mount stage while apply logs manually not data guard is used.
We have increase size or online redo log in primary . Now want to inrease in standby database also.
how to increase the size of current online redo log in standby database while it in mount stage .
in mount stage we cant run alter system switch logfileuser11965804 wrote:
We have oracle 10g standby database. The standby database is always running in mount stage while apply logs manually not data guard is used.
We have increase size or online redo log in primary . Now want to inrease in standby database also.
how to increase the size of current online redo log in standby database while it in mount stage .
in mount stage we cant run alter system switch logfilein 10g Standby will be always in Mount status when MRP is running.
When you increase size of online redo log files in primary, You should increase in standby also..
Standby redo log file size should be equal or higher than primary. You no need to switch log files on Standby.
You will have only standby redo log files in standby not ORL(online redo log files)
You can use this below script to add standby redo log files.
http://www.pythian.com/news/581/oracle-standby-redo-logs/ -
About automatic disappearance of Redo log file
I had free Oracle9i Release 1(9.0.1) CD and I installed Oracle9i on my PC.
When using Database assistant to create a database(I choose not to create a database during installation of 9i), after clone of database, it will start database, error comes.
It says: Error write to redo01.log file, I check that file, it existed in the related folder, while at that time it disappears, once I had redo01, 02, 03 log file. It confused me.
Does anyone give something on that?
Thanks.Well, seriously you need to read basic oracle documents.
To give short answers to your question.
Redo logs are required for instance and crash recovery of your system.
You need to have minimum two redo groups with minimum one redo member for each group. They are written in a circular fashion, i.e. one after one. If you maintain your database in archivelog mode, before rewriting/reusing the filled redo group member, that will be archived through arch process to a archive file, this can be used for database recovery.
Every database must required two redo groups and you can't delete them.
Jaffar -
When occurs crash recovery,why use active online redo log not archived log?
If current redo log had archived, but it's still 'ACTIVE'. As we all know, archived log is just an archived copy of the current redo log which is still 'ACTIVE', they have the same data. But why use active online redo log not archived log for crash recovery?(I think, if crash recovery can use archived log, then whether the online redo log is 'ACTIVE' or not, it can be overwritten)
Quote:
Re: v$log : How redo log file can have a status ACTIVE and be already archived?
Hemant K Chitale
If your instance crashes, Oracle attempts Instance Recovery -- reading from the Online Redo Logs. It doesn't need ArchiveLogs for Instance Recovery.
TanelPoder
Whether the log is already archived or not doesn't matter here, when the instance crashes, Oracle needs some blocks from that redolog. Archivelog is just an archived copy of the redolog, so you could use either the online or achive log for the recovery, it's the same data in there (Oracle reads the log/archivelog file header when it tries to use it for recovery and validates whether it contains the changes (RBA range) in it what it needs).Aman.... wrote:
John,
Are you sure that the instance recovery (not the media recovery) would be using the archived redo logs? Since the only thing that would be lost is the isntance, there wouldn't be any archived redo log generated from the Current redo log and the previous archived redo logs, would be already checkpointed to the data file, IMHO archived redo logs won't participate in the instance recovery process. Yep, shall watch the video but tomorrow .
Regards
Aman....
That's what I said. Or meant to say. If Oracle used archivelogs for instance recovery, it would not be possible to recover in noarchive log mode. So recovery relies exclusively on the online log.
Sorry I wasted your time, I'll try to be less ambiguous in future -
Standby redo log group for particular thread
hi masters,
actually i am performing an experiment to create physical standbyt database on the same machine as my primary database.
i ma going according to 'data guard admin guide'. while section for ading standby redo log group,it says that you have to add standby redo log group to "thread"....
what is this thread? and how can i foind to which thread i have to assign the next redo log group??
how can i find current thread??
what if i dont add "to thread' clause in my statement:-
ALTER DATABASE ADD STANDBY LOGFILE THREAD 5
2> ('/oracle/dbs/log1c.rdo','/oracle/dbs/log2c.rdo') SIZE 500M;
thanks and regards
VDVikrant,
First a question: Do you have a RAC instance? If so the paragraph even doesn't apply to you and I'm not sure why you are questioning it.
Secondly
"The THREAD clause is required only if you want to add one or more standby redo log
file groups to a specific primary database thread. If you do not include the THREAD
clause and the configuration uses Real Application Clusters (RAC), Data Guard will
automatically assign standby redo log file groups to threads at runtime as they are
needed by the various RAC instances."
this means you dont have to specify thread for RAC,as it will allocate one according to current thread.
Your conclusion is incorrect.
Where do you read the word 'current'?
Oracle will likely simply make sure each instance has sufficient standby redolog groups, the requirement is 1 standby redolog group per group + 1 extra.
Sybrand Bakker
Senior Oracle DBA -
Hi,
DB: 10.2.0.4
OS: UNIX/Windows
I have some doubts in archive log generation.
*1)* Once current redo log is filed , LGWR will move to next redo log which is available with status INACTIVE , and current one will become ACTIVE.If more archive logs are generating , based on business , ACTIVE will become INACTIVE after sometime and can use for CURRENT redo log.
If no archive logs are generated , my redo log is not coming out from status ACTIVE to INACTIVE .Even i waited for 5 minutes , but i had the same status.
What will be the time to make ACTIVE to INACTIVE?. What causing to make this happen ?.
Normally , when checkpoint is happened DBWR will write the CURRENT log data to data files , right?.In ACTIVE state , has archive log generated?. Many times i seen archive log is generated even it is in ACTIVE state.
*2)* My Archive logs size (25MB) is not equal to the redo log size. Normally , when we switch the logs or any rman backup , logs will be switched automatically and how much redo is filled , same will be generated with size.
But, in my case , more archive logs are generating and many have the different size out of generated and no manual switching or rman script are running during this period.
Any idea on this?.
Thanks,
Sunandsunand wrote:
Hi,
DB: 10.2.0.4
OS: UNIX/Windows
I have some doubts in archive log generation.
*1)* Once current redo log is filed , LGWR will move to next redo log which is available with status INACTIVE , and current one will become ACTIVE.If more archive logs are generating , based on business , ACTIVE will become INACTIVE after sometime and can use for CURRENT redo log.
If no archive logs are generated , my redo log is not coming out from status ACTIVE to INACTIVE .Even i waited for 5 minutes , but i had the same status.
What will be the time to make ACTIVE to INACTIVE?. What causing to make this happen ?.
Normally , when checkpoint is happened DBWR will write the CURRENT log data to data files , right?.In ACTIVE state , has archive log generated?. Many times i seen archive log is generated even it is in ACTIVE state.
That is wrong.DBWR process write dirty blocks from database buffer cache to datafiles but not "CURRENT log data to data files".So if your current online log group is full then ARCH process will try archiving this group to available destination and without archiving there will not happen LOG SWITCH.After archiving log switch will happen and LOG SEQUENCE NUMBER will increase then you will get new current log group.IF old group status is ACTIVE it means this group still need instance recovery.SO when you execute ALTER SYSTEM CHECKPOINT in this case status of this group will INACTIVE.
*2)* My Archive logs size (25MB) is not equal to the redo log size. Normally , when we switch the logs or any rman backup , logs will be switched automatically and how much redo is filled , same will be generated with size.
But, in my case , more archive logs are generating and many have the different size out of generated and no manual switching or rman script are running during this period.
Any idea on this?.
As you know archivelogs is a copy of online redologs,but there can be several reasons and result these size can be different.For example manual log switch or if you set ARCHIVE_LAG_TARGET != 0.Finally archive logs contains information for media recover,but online redo logs contain instance and media recovery it means these size can be different. -
Trying to archive more often: archive_lag_target vs downsizing redo logs
Hi,
I have a small production 10.2.0.1 database (small: all the files are 17GB total) on Linux which is used in Agile PLM. Ever since we went live, it produces only 2-4 archive logs per day. This was OK when our company was only concerned with being able to restore from the nightly cold backup. Now we want to make sure we can recover to the last hour of work. So I need the database to spit out more logs. It has 4 log groups (with 2 members each), each 50M in size. I am going to add 2 more log groups to have 6, since that is what we did for our 11i instance based on a consultants recommendation. That could prevent some problems, but won't cause it to spit out more logs. I did some research (here included) and found that setting archive_lag_target-3600 will FORCE the db to spit out logs every hour, and doing some testing, this works very nicely. The archive logs are only about 1.2M when they do get spit out every hour, but that is fine. The question is, is it OK to turn on archive_lag_target while keeping the size of the logs at 50M, and have mostly "small" logs being spit out? Or should I reduce the size of the logs to say 20M (by dropping the old ones and creating new ones)? I actually tried 20M and then during a busy time it spit out 2 of them within 10 minutes, but then I looked and saw it did the same thing with the 50M size, so I figured why not keep the 50M redo log size in the first place? It would actually make my go-live plan easier as I would just add 2 log groups at the current size in prod, and not have to drop and recreate a bunch of logs. I think this is a good plan -- my only worry is that if traditionally the way to increase the frequency of the logs was to reduce their size, I feel like I am "cheating" by using the archive_lag_target parameter to do this. I also want to not change too many things at once in production at one time. Thanks in advance. Marvuser11965205 wrote:
is, is it OK to turn on archive_lag_target while keeping the size of the logs at 50M, and have mostly "small" logs being spit out?Yes it is OK: you should keep "large" redo log in case your database instance has sometimes much more write activity to avoid checkpoint not complete issue.
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