RMAN x Online redo logs - doubt

When using RMAN's online hot backup, RMAN does not back up the online redo logs, does it?
Is there a way to do that?

The online redo logs files are never backed up by RMAN or any hot backup method.
The online redo logs files contain the latest data or redo generated by the database.(The data comes from redo log buffer written by LGWR).
The contents of the current redo logs are not archived until a log switch occurs.
This means if all your members in a redo log group fails, you would lose the latest information. So its best practice to invoke log switch before starting archivelog backup.

Similar Messages

Can u we take online redo log backups using RMAN......can any one guide me

can u we take online redo log backups using RMAN.....in 1og

'Backup' solution for online redo logs is multiplexing (members of a group on different independent drives).
Werner

Can we use online redo log to recover lost datafile in NOARCHIVE mode?

I am working on OCA exam and confued about these 2 sample questions. (similar questions with totally different answer)
Please give me hint about the different between these 2 questions.
** If the database is in NOARCHIVELOG mode, and one of the datafile for tablespace USERS is lost, what kind of recovery is possible? (answer: B)
A. All transactions except those in the USERS tablespace are recoverable up to the loss of the datafile.
B. Recovery is possible only up to the point in time of the last full database backup.
C. The USERS tablespace is recoverable from the online redo log file as long as none of the redo log files have been reused since the last backup.
D. Tablespace point in time recovery is available as long as a full backup of the USERS tablespace exists.
** The database of your company is running in the NOARCHIVELOG mode. You perform a complete backup of the database every night. On Monday morning, you lose the USER1.dbf file belonging to the USERS tablespace. Your database has four redo log groups, and there have been two log switches since Sunday night's backup.
Which is true (answer: B)
A. The database cannot be recovered.
B. The database can be recovered up to the last commit.
C. The database can be recovered only up to the last completed backup.
D. The database can be recovered by performing an incomplete recovery.
E. The database can be recovered by restoring only the USER!.dbf datafile from the most recent backup.

I think Gaurav is correct, you can recover to the last commit even in NOARCHIVELOG, as long as all the changes in the redo logs have not been overwritten. So answer should be B for question 2.
Here is my test:
SQL> select log_mode from v$database;
LOG_MODE
NOARCHIVELOG
SQL> select tablespace_name, file_name from dba_data_files;
TABLESPACE_NAME
FILE_NAME
USERS
C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\USERS01.DBF
SYSAUX
C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\SYSAUX01.DBF
UNDOTBS1
C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\UNDOTBS01.DBF
SYSTEM
C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\SYSTEM01.DBF
DATA
C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\DATA01.DBF
SQL> create table names
2 ( name varchar(16))
3 tablespace users;
Table created.
so this segment 'names' is created in the datafile users01.
At this point I shut down and mount the DB, then:
RMAN> backup database;
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:29
Finished backup at 06-OCT-07
SQL>alter database open
SQL> insert into names values ('pippo');
1 row created.
SQL> commit;
Commit complete.
SQL>shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
At this point I delete datafile users01 and restart:
SQL> startup
ORACLE instance started.
Total System Global Area 167772160 bytes
Fixed Size 1247900 bytes
Variable Size 67110244 bytes
Database Buffers 96468992 bytes
Redo Buffers 2945024 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
ORA-01110: data file 4: 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\USERS01.DBF'
restoring the backup taken before inserting the value 'pippo' in table names:
RMAN> restore database;
Starting restore at 06-OCT-07
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile backupset restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\SYSTEM01.D
BF
restoring datafile 00002 to C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\UNDOTBS01.
DBF
restoring datafile 00003 to C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\SYSAUX01.D
BF
restoring datafile 00004 to C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\USERS01.DB
F
restoring datafile 00005 to C:\ORACLE\PRODUCT\10.2.0\ORADATA\ORA101RC\DATA01.DBF
channel ORA_DISK_1: reading from backup piece C:\ORACLE\PRODUCT\10.2.0\DB_1\DATA
BASE\0AITR52K_1_1
channel ORA_DISK_1: restored backup piece 1
piece handle=C:\ORACLE\PRODUCT\10.2.0\DB_1\DATABASE\0AITR52K_1_1 tag=TAG20071006
T181337
channel ORA_DISK_1: restore complete, elapsed time: 00:02:07
Finished restore at 06-OCT-07
RMAN> recover database;
Starting recover at 06-OCT-07
using channel ORA_DISK_1
starting media recovery
media recovery complete, elapsed time: 00:00:05
Finished recover at 06-OCT-07
SQL> alter database open;
Database altered.
SQL> select * from names;
NAME
pippo
SQL>
enrico

Physical Standby Online Redo log files,

Hi,
I'm trying to create a physical standby database (10.2.0.3). I'm a little confused about the requirement for online redo logs on the standby.
in my standby alert log I get the following when I issue:
SQL> alter database recover managed standby database disconnect from session
"ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/appl/oradata/prod/prod_1_redo_01_02.log'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3"
/appl/oradata/prod/prod_1_redo_01_02.log is the path to the location of the online redo logs on the production system. This file does not exist on the standby filesystem so the error is correct.
I assume that it gets this information from the standby control file I created on the production system and copied over to the standby.
Do I need to copy the online redo logs from the primary over to the standby site or do I need to create online redo logs on the standby?
Does the standby need to have redo log files?
I'm not talking about 'standby log files' of the type created using 'alter database add standby log file'. I've not got that far yet.
I just need to establish if a physical standby requires online redo log files?
Thanks in advance,
user234564

I wanted to update this thread since I've been dealing with the exact same errors. The basic question is: "does a physical standby need the online redo logs?"
Answer: Not really, until one wants to switchover or failover (and become a primary database). Furthermore, whenever the MRP process is started, Oracle prepares for a possible switchover/failover by "clearing" the online redo logs (MetaLink note# 352879.1). It is not a big deal, since Oracle will build the actual redo files when the "alter database open resetlogs" is accomplished during a "role transition."
In our situation, we have decided to use our standby for nightly exports. We stop MRP, open the database read-only, then restart MRP. We built these standby DBs with RMAN. The RMAN duplicate process will not build the online redo log files until the database is opened for read/write (with resetlogs). However, we haven't had a need for read/write (i.e. a switchover).
Thus, every morning we have been getting the same errors that "user234564" posted above. At first the errors seemed scary, then we realized they were just a nusiance. In order to clean things up, all I did was just "cp" our stanby redo logs (SRL) into our online redo directories ensuring the names matched what was in v$logfile. When I restarted MRP, the alert log clearly showed Oracle clearing these "newly found" online redo logs.

The file structure online redo log, archived redo log and standby redo log

I have read some Oracle documentation for file structure and settings in Data Guard environment. But I still have some doubts. What is the best file structure or settings in Oracle 10.2.0.4 on UNIX for a data guard environment with 4 primary databases and 4 physical standby databases. Based on Oracle documents, there are 3 redo logs. They are: online redo logs, archived redo logs and standby redo logs. The basic settings are:
1. Online redo logs --- This redo log must be on Primary database and logical standby database. But it is not necessary to be on physical standby database because physical standby is not open. It doesn't generate redo log. However, if don't set up online redo log on physical standby, when primary failover and switch standby as primary. How can standby perform without online redo logs? In my standby databases, online redo logs have been set up.
2. Archived redo logs --- It is obviously that primary database, logical and physical standby database all need to have this log file being set up. Primary use it to archive log files and ship to standby. Standby use it to receive data from archived log and apply to database.
3. Standby redo logs --- In the document, it says A standby redo log is similar to an online redo log, except that a standby redo log is used to store redo data received from another database. A standby redo log is required if you want to implement: The maximum protection and maximum availability levels of data protection and Real-time apply as well as Cascaded destinations. So it seems that this standby redo log only should be set up on standby database, not on primary database. Am my understanding correct? Because I review current redo log settings on my environment, I have found that Standby redo log directory and files have been set up on both primary and standby databases. I would like to get more information and education from experts. What is the best setting or structure on primary and standby database?

FZheng:
Thanks for your input. It is clear that we need 3 type of redo logs on both databases. You answer my question.
But I have another one. In oracle ducument, it says If you have configured a standby redo log on one or more standby databases in the configuration, ensure the size of the current standby redo log file on each standby database exactly matches the size of the current online redo log file on the primary database. It says: At log switch time, if there are no available standby redo log files that match the size of the new current online redo log file on the primary database. The primary database will shut down
My current one data gurard envirnment setting is: On primary DB, online redo log group size is 512M and standby redo log group size is 500M. On the standby DB, online redo log group size is 500M and standby redo log group size is 750M.
This was setup by someone I don't know. Is this setting OK? or I should change Standby Redo Log on standby DB to 512M to exactly meatch with redo log size on primary?
Edited by: 853153 on Jun 22, 2011 9:42 AM

Clearing Online redo logs on the target physical standby

Hi,
Version 11202.
Primary on machine A
Standby on machine B
Following note: 11.2 Data Guard Physical Standby Switchover Best Practices using SQL*Plus [ID 1304939.1].
Online redo logs on the target physical standby need to be cleared before that standby database can become a primary database. And later :
On the target physical standby run the following query to determine if the online redo logs have not been cleared... 1) I did not understand where i should run the query. On machine A or on machine B ?
2)
Online redo logs on the target physical standby need to be CLEARED
What does it mean that it need to be CLEARED ? Does transaction might be lost by running the clearing command?
Thanks

I have used my note many times in production.
For example they needed to do some power work on the main server room a few months back on the weekend.
We did switchovers until the work was complete and then a switch back.
I wrote a short document called "Switchover post-mortem lessons" the main point from that was :
1.
getting ORA-01017 issues in Oracle forms ( Application ) after the switchover to standby.
The issue was caused by the Standby database having a different parameter for passwords than the Primary database.
This did not show up in testing because all the tester we used had converted passwords from Oracle 10.
Solution
When in doubt issue this on the new Primary :
SQL>ALTER SYSTEM SET SEC_CASE_SENSITIVE_LOGON = FALSE;
Note: This command can be issued repeatedly with no negative effect on the system.2.
The query to check switch_over status was returning "LOG SWITCH GAP"
select switchover_status from v$database;
This is an issue because Oracle says the return values should be one of these :
NOT ALLOWED
SESSIONS ACTIVE
SWITCHOVER PENDING
SWITCHOVER LATENT
TO PRIMARY
TO STANDBY
RECOVERY NEEDED
LOG SWITCH GAP is not one of the expected value. In addition this phase is not search friendly either on the Oracle support site or your favorite search engine.
Given this I ran this query :
SELECT
NAME AS STANDBY,
SEQUENCE#,
APPLIED,
COMPLETION_TIME
FROM
V$ARCHIVED_LOG;
Solution
SQL>ALTER SYSTEM SWITCH LOGFILE;
And wait a few minutesMy switchover document had no issue.
Best Regards
mseberg

Online redo logs vs backup

Below quoted sentence is from Oracle documentation
"Online redo logs, unlike archived logs, should never be backed up. The chief danger
associated by having backups of online redo logs is that you may accidentally restore
those backups without meaning to, and corrupt your database"
Can any one explain , how the database will be corrupted if we backup online redo logs. I am having a hard time to understand this quote
thanks for your help
shajan

Redo log file contents is very dynamic. It changes minute after minute, so a backup is useless if you try to do it online. (In fact there is no command to perform such backup).
Let's suppose you shutdown (normal, immediate or transactional) The contents of the redo log files become useless as the checkpoint process has already taken place, so it is enough to have a copy of all of the consistent datafiles to have the last applied transaccion.
In a recovery scenario with archivelog it is important to keep all of the requiered archivelog files plus all of the online redo log files.
In case of a missing logfile it is useless to have a backup of it. If you ever had one, and you tried to restore it, an error would arise, warning you that the contents of the logfile is inconsistent with the expected scn. The only way you can succeed is to have them multiplexed and have them on different paths, just to reduce to probability of loosing all of the members of a group.
rman does not perform backup of redo log files. Classical theory of backup/recovery states that during a hot backup it must be backed up the archive log files, not the redo log files.

Online Redo logs instead of Standby Redo logs

RDBMS Version: 11.2.0.3/Platform : RHEL 6.3
To migrate a 3TB Database to a new DB server , we are going to use RMAN DUPLICATE.
Step1. Take full backup of DB + Standby Control file at primary site and transfer the Bkp files to Standby site
Step2. At standy site, we will run the RMAN duplicate target database for standby
After the above step, we don't want to create the standby redo logs because the newly restored DB in standby server is going to be the new Prod DB which application will be pointing to.
So, Can I skip the Standby Redo log creation part and create Online redo logs instead ?
As mentioned earlier, Our objective is not to create a proper Dataguard Standby DB setup. We just want to clone our DB to another server using RMAN Duplicate.

Tom wrote:
RDBMS Version: 11.2.0.3/Platform : RHEL 6.3
To migrate a 3TB Database to a new DB server , we are going to use RMAN DUPLICATE.
Step1. Take full backup of DB + Standby Control file at primary site and transfer the Bkp files to Standby site
Step2. At standy site, we will run the RMAN duplicate target database for standby
After the above step, we don't want to create the standby redo logs because the newly restored DB in standby server is going to be the new Prod DB which application will be pointing to.
So, Can I skip the Standby Redo log creation part and create Online redo logs instead ?
As mentioned earlier, Our objective is not to create a proper Dataguard Standby DB setup. We just want to clone our DB to another server using RMAN Duplicate.
Hi,
Take full backup of DB + Standby Control
We just want to clone our DB to another server using RMAN Duplicate
If you want only clone database of production, why you are take Standby controlfile?
If you don't want create standby database then, why you using DUPLICATE command with FOR STANDBY option.
You can use DUPLICATE command for clone database, without for standby option.
If you say no, we want create standby database and we will perform swithover,
then yes, you can use online redo logs for max performance mode.
and you can create standby redo logs on all database, but this redo logs will use by database when database role
is standby.
Regards
Mahir M. Quluzade

Backup online redo log files

Hi All
Can you please explain for me the main reason that we do not have to backup the online redo log using RMAN ?
Thanks

The online redo logfiles are necessary to perform a complete recovery of the database. During database recovery, Oracle will apply the archived redo logfiles and online redo logfiles to roll the database forward and finally remove uncommitted transactions. If any of the online redo logfile group is active and missing, the database recovery will be incomplete and the database needs to be opened with restlogs, causing a new database incarnation.
You have to shutdown the datrabase to be able to perform a backup of the online redo logfiles, or find another method to create a time based snapshot of the data to prevent data movement while the redo logfiles are in use in order to keep datafile headers, controlfile and redo logfiles in sync. It is for that reason that you multiplex and mirror redo logfiles.

Full Online + REDO Log backup failing

Hi Experts,
We have a failing backup when running a 'Full Online + REDO Logs' scheduled via DB13 (ERP6/Windows 2008/Oracle 10.2.0.4)
Whilst it is successful in backing up the datafiles and the REDO logs to the remote destination, it fails to catalog the backup, displaying the following message:
ORA-19625: error identifying file
Backup_Destination\BEFSDJTA\SR3.DATA10
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 5) Access is denied.
RMAN>
Recovery Manager complete.
BR0280I BRBACKUP time stamp: 2011-04-21 07.20.49
BR0279E Return code from 'F:\oracle\SID\102\BIN\rman nocatalog': 1
BR0536E RMAN call for database instance EQ1 failed
BR0280I BRBACKUP time stamp: 2011-04-21 07.20.49
BR0532E Cataloging backups of all database files failed
From what I understand, RMAN runs under the OracleService<SID> service, which calls the oracle.exe process, which is owned by the local user SYSTEM. This accounts for the access denied problem when accessing the remote destination using the RMAN utility.
As a test, I'm aware that if I change the ownership of oracle.exe to a non-local, domain user (<SID>adm), I can run RMAN commands without the permission denied error occuring. (performed this on a Sandbox)
The problem when I use this <SID>adm account as the oracle.exe owner, is that the SAP application Work Processes won't connect to oracle.
My questions are:
Is it a valid workaround to change the process owner of oracle.exe to something other than the local SYSTEM user?
If so, what are the criteria that need to be met for the new domain user to ensure that the SAP application is stable?
Does anyone know of an alternative workaround?
Thanks,
Chris W

Hi Markus,
Thanks for the response.
I've managed to get the SAP application to run with Oracle using the <SID>adm account as the OracleService<SID> owner.
The original problem with the SAP work processes in connecting with the Oracle database was due to the Oracle listener services also being owned by local user SYSTEM.
I changed the listener services ownership to <SID>adm (as well as the OracleService<SID>) and this allowed the connection between the SAP work processes and Oracle.
Also, I gave the domain <SID>adm account local administrator rights (same as SYSTEM) and have seen no problems since the switch.
I can also access a remote host using the RMAN utility - problem appears to be solved.
Chris

Regarding Online Redo log backup

Dear all,
I am running "Whole database online + Redo log backup" in production server which running successfully with return code 0000.
Is this backup takes online redo log file also?????? because in backup log i didn't see any directory like .../../orilog A, .../../orilog B etc which contains online redo log file.
Without this online redo log backup i don't thing we can do point to point recovery.
I am beginner for oracle so please clear this doubt.
thanks,
Tarun

Tarun verma wrote:
> Oraarch having offline redo log file and saparch having redo log backup log file, but both of this related to offline redo log backup.
>
> I want to know about online redolog backup??? Is it possible to take or not??? and how we can check online redo log backup is running or not??
You have offline redo log files in 'oraarch' --> this means that 'online redo logs' are getting backed up into 'oraarch'.
sql > archive log list
http://www.adp-gmbh.ch/ora/sqlplus/archive_log.html
Above command tells whether the logging is ON or not. If it is ON, then online logs will be generated w.r.t. every sap work and as soon as the online logs gets filled up - it gets backed up into 'oraarch' - to accommodate more logging with time.
Thanks

Open database if an active online redo log is missing

Hi,
Sorry for the rather long post, but I specified all the steps I performed and couldn't make it shorter :-(
I need an advice on how to open the database if an active online redo log is missing.
For test purposes I intentionally performed a shutdown abort when the redo log group 1 was in active state and then renamed its only member (REDO01.LOG) so that the database couldn't perform crash recovery using it. Then upon startup I obviously got the message:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.Ok, so I checked the state of the logs:
{noformat}
SQL>SELECT a.GROUP#, first_change#, SEQUENCE#, a.status, SUBSTR(b.MEMBER, 1, 40) MEMBER, b.status mem_status, a.archived
2    FROM v$log a, v$logfile b
3   WHERE a.GROUP# = b.GROUP#
4 ORDER BY a.GROUP#, b.MEMBER;
GROUP# FIRST_CHANGE# SEQUENCE# STATUS           MEMBER                         MEM_STA ARC
     1        592134         29 ACTIVE           H:\ORADATA\TESTDB\REDO01.LOG           YES
     2        592268         30 CURRENT          C:\ORADATA\TESTDB\REDO02.LOG           NO
     3        592129         28 ACTIVE           C:\ORADATA\TESTDB\REDO03.LOG           YES
{noformat}Since opening the database to perform a log switch and thus change the status of the redo log group 1 from ACTIVE to INACTIVE to recreate the member isn't possible, I performed database recovery.
SQL>recover database until cancel;
ORA-00279: change 592129 generated at 02/04/2009 10:31:15 needed for thread 1
ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_28_%U_.ARC
ORA-00280: change 592129 for thread 1 is in sequence #28
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
ORA-00279: change 592134 generated at 02/04/2009 10:31:28 needed for thread 1
ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_%U_.ARC
ORA-00280: change 592134 for thread 1 is in sequence #29
ORA-00278: log file 'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_28_4RLR3JS9_.ARC' no longer needed for this rec
overy
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_4RLR4MF3_.ARC'
ORA-00279: change 592268 generated at 02/04/2009 10:32:03 needed for thread 1
ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_30_%U_.ARC
ORA-00280: change 592268 for thread 1 is in sequence #30
ORA-00278: log file 'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_4RLR4MF3_.ARC' no longer needed for this rec
overy
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
'C:\ORADATA\TESTDB\REDO02.LOG'
Log applied.
Media recovery complete.
SQL>So for log sequence #28 I accepted the proposed archived redo log in the FRA, for sequence #29 (that's the online redo log that is missing!) I manually specified its archived copy, and for sequence #30 I specified the CURRENT online redo log. And as it seems the media recovery was successful.
Next I tried to open the database but again got the error:
SQL>alter database open noresetlogs;
alter database open noresetlogs
ERROR at line 1:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.
The status of the log groups and its members is exactly as it was in the first query I wrote above, i.e. the redo log group 1 is still ACTIVE, so it's needed for crash recovery (which I had already done manually if I understand correctly how Oracle works!). I also checked if the datafiles are inconsistent (described in metalink doc id 1015544.102):
SQL>SELECT DISTINCT CHECKPOINT_CHANGE#, FUZZY FROM V$DATAFILE_HEADER;
CHECKPOINT_CHANGE# FUZ
            592269 NOSo, everything seems ok as far as datafile consistency is concerned.
My question is: how can I rename/drop/clear/whatever the member of redo log group 1 to open the database?
I tried to rename the log file member, to add another member to it, to open the database with resetlogs, to clear the logfile group 1, but all without success:
1)
SQL>alter database clear logfile group 1;
alter database clear logfile group 1
ERROR at line 1:
ORA-01624: log 1 needed for crash recovery of instance testdb (thread 1)
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
2)
SQL>alter database open resetlogs;
alter database open resetlogs
ERROR at line 1:
ORA-01139: RESETLOGS option only valid after an incomplete database recovery
3)
SQL>alter database rename file 'H:\ORADATA\TESTDB\REDO01.LOG' to 'C:\ORADATA\TESTDB\REDO01.LOG';
alter database rename file 'H:\ORADATA\TESTDB\REDO01.LOG' to 'C:\ORADATA\TESTDB\REDO01.LOG'
ERROR at line 1:
ORA-01511: error in renaming log/data files
ORA-01512: error renaming log file H:\ORADATA\TESTDB\REDO01.LOG - new file C:\ORADATA\TESTDB\REDO01.LOG not found
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.
4)
SQL>alter database add logfile member 'C:\ORADATA\TESTDB\REDO01.LOG' to group 1;
alter database add logfile member 'C:\ORADATA\TESTDB\REDO01.LOG' to group 1
ERROR at line 1:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.Sorry again for the long post and thank you in advance for any suggestion.
Regards,
Jure

You could check if the recovery was complete by (re)creating the controlfile with the resetlogs option.
<CREATE CONTROLFILE REUSE DATABASE define_db_name RESETLOGS NOARCHIVELOG
...>Thanks for the hint. If possible, could you only check if the steps I'm going to perform are ok.
I did an "alter database backup controlfile to trace;" and then extracted the create controlfile definition part. So in essence I should run the following statements:
CREATE CONTROLFILE REUSE DATABASE "TESTDB" RESETLOGS ARCHIVELOG
    MAXLOGFILES 16
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 8
    MAXLOGHISTORY 292
LOGFILE
GROUP 1 'C:\ORADATA\TESTDB\REDO01.LOG' SIZE 20M,
GROUP 2 'C:\ORADATA\TESTDB\REDO02.LOG' SIZE 20M,
GROUP 3 'C:\ORADATA\TESTDB\REDO03.LOG' SIZE 20M
-- STANDBY LOGFILE
DATAFILE
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSTEM01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\UNDOTBS01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSAUX01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\USERS01.DBF'
CHARACTER SET EE8MSWIN1250
ALTER DATABASE OPEN RESETLOGS;
ALTER TABLESPACE TEMP ADD TEMPFILE 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\TEMP01.DBF' REUSE;Is that correct?
About the RMAN backups: Wouldn't a 'CATALOG RECOVERY AREA' populate the controlfile with backup information again (I'm not using a recovery catalog in this case)?
Thanks for the help!
Regards,
Jure

DB STARTUP 시 ORA-312, ORA-313(ONLINE REDO LOG CRASH)

제품 : ORACLE SERVER
작성날짜 : 2002-10-31
=====================================================
DB STARTUP 시 ORA-312, ORA-313(ONLINE REDO LOG CRASH)
=====================================================
PURPOSE
[ ONLINE REDO LOG가 손상되었을 때 DB에 OPERATION 이 없었던 경우는 다음과 같은 절차로 DB 을 OPEN 할 수 있다. - 확률 70% ]
Explanation & Example
1. CONTROLFILE 생성
-. 손상된 online log 는 포함시키지 않는다.
-. resetlogs option 으로 생성한다.
-. reuse option 은 생략하고 기존 controlfile 은 다른 이름으로 move 시킴.
<V7 에서 CONTROLFILE 생성하는 방법 >
sqldba> startup mount
sqldba> alter database backup controlfile to trace;
위와 같이 명령을 입력하면 ORACLE_HOME/rdbms/log 디렉토리에 trace 화일이
생긴다. 그 trace 화일에서 create controlfile 명령 부분을 남기고 삭제
한다.
(7.3 이상에서는 cd $ORACLE_HOME
cd ../../admin/SID dir/udump 에 있습니다.)
콘트롤 화일 생성 문장 예 - <cnt.sql> : GROUP 1 이 ONLINE LOG 라고 가정
CREATE CONTROLFILE DATABASE "RC722" RESETLOGS NOARCHIVELOG
MAXLOGFILES 32 ********
MAXLOGMEMBERS 2
MAXDATAFILES 30
MAXINSTANCES 8
MAXLOGHISTORY 800
LOGFILE
GROUP 2 '/oracle/oracle/dbs/log2RC722.dbf' SIZE 5M,
GROUP 3 '/oracle/oracle/dbs/log3RC722.dbf' SIZE 5M
DATAFILE
'/oracle/oracle/dbs/systRC722.dbf',
'/oracle/oracle/dbs/rbsRC722.dbf',
'/oracle/oracle/dbs/toolRC722.dbf',
'/oracle/oracle/dbs/usrRC722.dbf',
'/oracle/oracle/dbs/tempRC722.dbf',
'/oracle/oracle/rcdata.dbf'
2.절차
$ sqldba lmode=y
SQLDBA> connect internal
SQLDBA> shutdown abort
SQLDBA> startup nomount
statement processed
SQLDBA> @cnt
SQLDBA> recover database using backup controlfile until cancel;
CANCEL (Return)
Recovery canceled
SQLDBA> alter database open resetlogs;
: 만일 정상적으로 open 되면 log file 추가
SQLDBA> alter database add logfile '?/dbs/log1ORA722.dbf' size 1M;
Reference Documents
none

You could check if the recovery was complete by (re)creating the controlfile with the resetlogs option.
<CREATE CONTROLFILE REUSE DATABASE define_db_name RESETLOGS NOARCHIVELOG
...>Thanks for the hint. If possible, could you only check if the steps I'm going to perform are ok.
I did an "alter database backup controlfile to trace;" and then extracted the create controlfile definition part. So in essence I should run the following statements:
CREATE CONTROLFILE REUSE DATABASE "TESTDB" RESETLOGS ARCHIVELOG
    MAXLOGFILES 16
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 8
    MAXLOGHISTORY 292
LOGFILE
GROUP 1 'C:\ORADATA\TESTDB\REDO01.LOG' SIZE 20M,
GROUP 2 'C:\ORADATA\TESTDB\REDO02.LOG' SIZE 20M,
GROUP 3 'C:\ORADATA\TESTDB\REDO03.LOG' SIZE 20M
-- STANDBY LOGFILE
DATAFILE
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSTEM01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\UNDOTBS01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSAUX01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\USERS01.DBF'
CHARACTER SET EE8MSWIN1250
ALTER DATABASE OPEN RESETLOGS;
ALTER TABLESPACE TEMP ADD TEMPFILE 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\TEMP01.DBF' REUSE;Is that correct?
About the RMAN backups: Wouldn't a 'CATALOG RECOVERY AREA' populate the controlfile with backup information again (I'm not using a recovery catalog in this case)?
Thanks for the help!
Regards,
Jure

What is the difference between undo tablespace and online redo log files.

what is the difference between undo tablespace and online redo log files. I am confused
as per my knowledge undo tablespace is used to store the undo information when a table is being updated so that, just incase we need to rollback a transaction we know what was present in the table earlier.
when a transaction fails the SMON performs the rollback of the data.
This undo data is stored in the undo tablespace and read consistency if any is enforced.
is my understanding till here correct?
Now, can this undo data/before image not be stored in the redo log buffer and online redolog files?
can redo-log files not store this information?
in fact, is it that when undo tablespaces exist in a database, the undo data/before image is stored in both the undo tablespace and also the redo log files?
kindly clarify my doubt.
thank you.

This question has been asked many times before. The answer is always the same.
Yes, redo contains the before image of data (and the after-image). Therefore, it **COULD** be used to roll back a transaction.
BUT... Redo is written sequentially. Using it to rollback your transaction would involve reading through all the redo written by maybe thousands of other people. It would be painfully slow.
Your transaction is, however, directly linked to just the UNDO that it generates (which is JUST the before image of the data). So, your undo is your undo and doesn't share space with anyone else's undo. Therefore, using it to roll back YOUR transaction is fast.
The fact that undo is only the before image of the data also makes it faster than wading through a sea of before and AFTER images as you'd find in redo. About twice as fast, in fact, since there's half the data. Roughly.
Redo also gets written and flushed to disk whenever there's a commit, 3 seconds are up or too much (1MB, actually) redo gets generated between flushes caused by other factors. Your redo gets flushed when those things happen, even if you haven't actually committed your transaction. And redo logs recycle themselves, meaning that your redo -even if your transaction hasn't been committed yet- can be over-written by later transactions. Try rolling back when that's happened, if redo was the source of your rollback data!
Undo, however, cannot be over-written if the transaction has not been committed. Ever. If you don't commit for three years, there will be three years' undo stored in your database (assuming you had the space, of course!).
I could go on, but that will do. Redo is there fore RECOVERY, after catastrophe. Undo is there for read-consistency (and the occasional change of mind). Two different functions. Two different mechanisms. Each one highly tuned to doing what it does, why it does it, most efficiently and effectively.

Best practice - online redo logs and virtualization

I have a 10.1.0.4 instance (soon to be migrated to 11gr2) running under Windows Server 2003.
We use a non-standard disk distribution scheme -
on the c: drive we have oracle_home as well as directories for control files and online redo logs.
on the d: drive we have datafiles
on the e: drive we have archive log files and another directory with online redo logs and another copy of control file
my question is this:
is it smart practice to have ANY online redo logs or control file on the same spindle with archive logs?
Our setup works fairly well but we are in the process of migrating the instance first to ESX server and SAN and then secondly to 11gtr2 64bit under server 2008 64 and when we bring up our instance on the VM for testing we find that benchmarking the ESX server (dual Xeon 3.4ghz with 48gb RAM running against FalconStor NSS SAN with 15k SAS disks over iSCSI) against the production physical server (dual Xeon 2.0ghz with 4gb RAM using direct attached SATA 7200rpm drives) we find that some processes run faster on the ESX box and some run 40-100% slower. Running Statspack seems to identify lots of physical read waits as well as some waits for redo and controlfiles.
Is it possible that in addition to any overhead introduced by ESX and iSCSI (we are running Jumbo Frames over 1gb) we may have contention because the archive logs are on the same "spindle" (virtual) as the online redo and control files?
We're looking at multiple avenues to bring the 2 servers in line from a performance standpoint - db configuration, memory allocation, possible move to 10gb network, possible move to SSD storage tray, possible application rewrites. But from the simplest low hanging fruit idea, if these files should not be on the same spindle thats an easy change to make and possibly eke out an improvement.
Ideas?
Mike

Hi,
"Old" Oracle standard is to use as many spindles as possible.
It looks to me, you have only 1 disk with several partitions on it ??
In my honest opinion you should anyway start by physically seperating OS from Oracle, so let the C: drive to the Windows OS
Take another physical seperate D: drive to install you application.
Use yet another set of physical drives, preferably in RAID10 setup, for your database and redo logs
And finally yet another disk for the archive logs.
We have recently configured a Windows 2008 server with an 11G Db, which pretty much follows the above setup.
All non RAID10 disks are RAID1 ( mirror ) and we even have some SSD's for hot tables and redo-logs.
The machine, or must I say the database, operates like a high speed train, very, very fast.
Ofcourse keep in mind the number of cores ( not only for licensing ) and the amount of memory.
Try to prevent the system from swapping, because that is a performance killer!
Edit: And even if you put a virtual layer in between, try to seperate the virtual disks as much as possible over physical disks
Success!
FJFranken
Edited by: fjfranken on 7-okt-2011 7:19

RMAN x Online redo logs - doubt

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