Online redo logs

Hi,
I need to move online redo logs to the folder where data files reside. It will be easier for cold back up in NOARCHIVE mode. At the same time I would like recovery_flash_area unattached.
The Beta version was perfect for that purpose. I already moved SPFILE.
Can somebody explain how to move only those two files to C:\oraclexe\oradata\XE?
Konstantin

Relocating and Renaming Redo Log Members
Thank you Forbrich and others from the forum! I have solved the problem tanks to your help.
There are some slightly differences from Oracle® Database Administrator's Guide
10g Release 2 (10.2) Part Number B14231-01 and APEX for Win XP.
1. SQL Statements
SQL*Plus: Release 10.2.0.1.0 - Production on Thu May 25 19:37:04 2006
Copyright (c) 1982, 2005, Oracle. All rights reserved.
SQL> connect / AS SYSDBA
Connected.
SQL> SHUTDOWN
Database closed.
Database dismounted.
ORACLE instance shut down.
/* Then using OS (Windows Explorer) copy two files to the new folder. */
SQL> STARTUP MOUNT XE
ORACLE instance started.
Total System Global Area 314572800 bytes
Fixed Size 1287184 bytes
Variable Size 243272688 bytes
Database Buffers 67108864 bytes
Redo Buffers 2904064 bytes
Database mounted.
SQL> ALTER DATABASE RENAME FILE 'C:\ORACLEXE\APP\ORACLE\FLASH_RECOVERY_AREA\XE\ONLINELOG\O1_MF_2_25T0KHLK_.LOG','C:\ORACLEXE\APP\ORACLE\FLASH_RECOVERY_AREA\XE\ONLINELOG\O1_MF_1_25T0KF00_.LOG' TO 'C:\ORACLEXE\ORADATA\XE\O1_MF_2_25T0KHLK_.LOG','C:\ORACLEXE\ORADATA\XE\O1_MF_1_25T0KF00_.LOG';
Database altered.
SQL> ALTER DATABASE OPEN;
Database altered.
SQL> EXIT
2. APEX for Win XP automatically erases redo log files.
Everything works OK
Konstantin
Message was edited by:
konstantin.gudjev

Similar Messages

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

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

Moving the online redo log files to different location

We just installed few more drives into our sandbox system and I want to move the online redo log files for better performance. We've got the SAPARCH directory moved to a different location.
Does anyone know how/where I can change the parameters so redo log files are pointed at different drives? It's not in the <b>init<SID>.ora</b> file...
Regards,
Sumit

Hi Sumit,
The following link contains information about moving the redo logs:
http://www.stanford.edu/dept/itss/docs/oracle/9i/server.920/a96521/onlineredo.htm
Best regards,
Alwin

Online redo log files being removed physically

Grid Infra version: 11.2.0.4
RDBMS Version: 11.2.0.4
Although this is a RAC DB, this is not a RAC-specific question. Hence posting it here.
Few months back, I remember issuing a command similair to below (DROP LOGFILE GROUP ...) and the redo log files were still physically present in the diskgroup.
If I remember correctly, the file is not deleted physical so that we can use the REUSE functionality (ALTER DATABASE ADD LOGFILE MEMBER '+REDO/orcl/onlinelog/redo1b.log' reuse to group 11; ) ie. you can use the REUSE command to add the logfile of the same name which is physically present in OS Filesystem/Diksgroup to redo log group.
But today, after I issued the below command, I checked the diskgroup location from ASMCMD
SQL> alter database drop logfile group 31;
Database altered.
From ASMCMD, I can that the file has disappeared physically. Is this a new feature with 11.2.0.4 or am I missing something here ?
ASMCMD> ls +DATA/msblprd/onlinelog/group_31.548.833154995
ASMCMD-8002: entry 'group_31.548.833154995' does not exist in directory '+DATA/msblprd/onlinelog/'

Just to add to what Aman has said.
It is a bad practice not to let OMF decide the placement of Online redo logs because of this issue especially when you use ASM.
Executing rm command in Linux/Unix is easy but Dropping ASM aliases in the disk group can be a hassle.
This is documented.
"When a redo log member is dropped from the database, the operating system file is not deleted from disk. Rather, the control files of the associated database are updated to drop the member from the database structure. After dropping a redo log file, ensure that the drop completed successfully, and then use the appropriate operating system command to delete the dropped redo log file."
http://docs.oracle.com/cd/E11882_01/server.112/e25494/onlineredo.htm#ADMIN11324
BTW . You don't even need to set db_create_online_log_dest_n to enable OMF for ORLs.
SQL> show parameter log_dest
NAME                                 TYPE        VALUE
db_create_online_log_dest_1          string
db_create_online_log_dest_2          string
db_create_online_log_dest_3          string
db_create_online_log_dest_4          string
db_create_online_log_dest_5          string
SQL> show parameter db_create_file_dest
NAME                                 TYPE        VALUE
db_create_file_dest                  string      +MBL_DATA
alter database add logfile thread 4
group 31 ('+MBL_DATA','+MBL_FRA') size 4096M,
group 32 ('+MBL_DATA','+MBL_FRA') size 4096M,
group 33 ('+MBL_DATA','+MBL_FRA') size 4096M,
group 34 ('+MBL_DATA','+MBL_FRA') size 4096M ;
Database altered.
And redo logs will be neatly placed as shown below
   INST     GROUP# MEMBER                                             STATUS           ARC
         4         31 +MBL_DATA/bsblprd/onlinelog/group_31.276.832605441 UNUSED           YES
                      +MBL_FRA/bsblprd/onlinelog/group_31.297.832605445 UNUSED           YES
                   32 +MBL_DATA/bsblprd/onlinelog/group_32.547.832605451 UNUSED           YES
                      +MBL_FRA/bsblprd/onlinelog/group_32.372.832605457 UNUSED           YES
                   33 +MBL_DATA/bsblprd/onlinelog/group_33.548.832605463 UNUSED           YES
                      +MBL_FRA/bsblprd/onlinelog/group_33.284.832605469 UNUSED           YES
                   34 +MBL_DATA/bsblprd/onlinelog/group_34.549.832605475 UNUSED           YES
                      +MBL_FRA/bsblprd/onlinelog/group_34.359.832605481 UNUSED           YES

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

Problem with Whole Database Online+Redo log Backup

Dear Marcus Sir,
I am facing while taking "Whole Database Online+Redo log Backup" through DB13 T-Code.
Below is the "Problem part of the Backup log", however if you need I will send you full log.
Hope you will find out problem soon
#FILE..... /oracle/ANP/sapdata2/sr3_8/sr3.data8
#SAVED.... sr3.data8 ANPB260810/12
BR0280I BRBACKUP time stamp: 2010-08-27 11.03.22
BR0063I 9 of 51 files processed - 19400.070 MB of 135986.469 MB done
BR0204I Percentage done: 14.27%, estimated end time: 11:47
BR0001I *******___________________________________________
BR0202I Saving /oracle/ANP/sapdata2/sr3_9/sr3.data9
BR0203I to /dev/rmt0.1 ...
BR0278E Command output of 'LANG=C dd obs=1024K bs=1024K if=/oracle/ANP/sapdata2/sr3_9/sr3.data9 of=/dev/rmt0.1':
dd read error: I/O error
462+0 records in
462+0 records out
BR0280I BRBACKUP time stamp: 2010-08-27 11.03.36
BR0279E Return code from 'LANG=C dd obs=1024K bs=1024K if=/oracle/ANP/sapdata2/sr3_9/sr3.data9 of=/dev/rmt0.1': 2
BR0222E Copying /oracle/ANP/sapdata2/sr3_9/sr3.data9 to/from /dev/rmt0.1 failed due to previous errors
BR0280I BRBACKUP time stamp: 2010-08-27 11.03.41
BR0317I 'Alter tablespace PSAPSR3 end backup' successful
BR0056I End of database backup: bedziydp.ant 2010-08-27 11.03.36
BR0280I BRBACKUP time stamp: 2010-08-27 11.03.41
BR0054I BRBACKUP terminated with errors
Warm Regards
Ahsan

Hi,
since you are getting a read error, it might as well be, that your datafile is defective.
Try the same dd-command to /dev/null, to see if it is possible to read the entire file.
First make sure that your null-device is existing, otherwise you might face a root-fs full problem.
dd obs=1024K bs=1024K if=/oracle/ANP/sapdata2/sr3_9/sr3.data9 of=/dev/null
or try a dbverify on it, which would also read the entire file and do a checksum test.
brbackup -c -u / -m /oracle/ANP/sapdata2/sr3_9/sr3.data9 -t online -w only_dbv
Good luck
Volker

Online redo logs on a physical standby?

A question on REDO logs on physical standby databases. (10.2.0.4 db on Windows 32bit)
My PRIMARY has 3 ONLINE REDO groups, 2 members each, in ..ORADATA\LOCP10G
My PHYSICAL STANDBY has 4 STANDBY REDO groups, 2 members each, in ..ORADATA\SBY10G
I have shipping occurring from the primary in LGWR, ASYNC mode - max availablility
However I notice the STANDBY also has ONLINE REDO logs, same as the PRIMARY, in the ..ORADATA\SBY10G folder
According to the 10g Dataguard docs, section 2.5.1:
"Physical standby databases do not use an online redo log, because physical standby databases are not opened for read/write I/O."
I have tried to drop these on the STANDBY when not in apply mode, but I get the following:
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
Database altered.
SQL> ALTER DATABASE DROP LOGFILE GROUP 3;
ALTER DATABASE DROP LOGFILE GROUP 3
ERROR at line 1:
ORA-01275: Operation DROP LOGFILE is not allowed if standby file management is
automatic.
I also deleted them while the STANDBY instance was idle, but it recreated them when moved to MOUNT mode.
So my question is why is my PHYSICAL recreating and using these, if the docs say the shouldn't?
I saw the same error mentioned here: prob. with DataGuard
Is this a case of the STANDBY needing at least a notion of where the REDO logs will need to be should a failover occur, and if the files are already there, the standby database CONTROLFILE will hold onto them, as they are not doing any harm anyway?
Or, is this a prooduct of having management=AUTOMATIC - i.e. the database will create these 'automatically'
Ta
bt

According to the 10g Dataguard docs, section 2.5.1:
"Physical standby databases do not use an online redo log, because physical standby databases are not opened for read/write I/O."yes, those are used when database is open.
You should not perform any changes in Standby. Even if those exist online redo log files, whats the difficulty you have seen?
These will be used whenever you performed switchover/failover. So nothing to worry on this.
Is this a case of the STANDBY needing at least a notion of where the REDO logs will need to be should a failover occur, and if the files are already there, the standby database CONTROLFILE will hold onto them, as they are not doing any harm anyway?Then oracle functionality itself harm if you think in that way. When they not used in open then what the harm with that?
Standby_File_management --> for example if you add any datafile, those information will be in archives/redos once they applied on standby those will be added automatically when it is set to AUTO if its manual, then it creates a unnamed file in $ORACLE_HOME/dbs location later you have to rename that file and recovery need to perform .
check this http://docs.oracle.com/cd/B14117_01/server.101/b10755/initparams206.htm
HTH.

Commit Completes although current online redo log file have been removed.

Although i have removed current online redo log file in linux os (Oracle Linux),when i type "commit" it says that "commit complete".
Is this fair for this princip?*:" if Only when all redo records associated with a given transaction are safely on disk in the online logs is the user process notified that the transaction has been committed."*
I think that it can lead to loss of data in some cases..I'm using Oracle 11g R2 on OEL (x64)..
Can anyone explain me ? I'm getting stuck in this situation..
P.S : I haven't multiplexed current ORL group files...

Javid wrote:
Although i have removed current online redo log file in linux os (Oracle Linux),when i type "commit" it says that "commit complete".
Is this fair for this princip?*:" if Only when all redo records associated with a given transaction are safely on disk in the online logs is the user process notified that the transaction has been committed."*
I think that it can lead to loss of data in some cases..I'm using Oracle 11g R2 on OEL (x64)..
Can anyone explain me ? I'm getting stuck in this situation..
In *nix, a file that is open by a process isn't really deleted until the process that has it completes. So even though you 'deleted' a redo log, oracle is still holding it. As soon as you stop your database (maybe even as soon as the db does a log switch) the redo will really be gone and no longer available. consider the implications for archive logging.
P.S : I haven't multiplexed current ORL group files...You need to fix that. the online logs are the achilles heel of the database. That's why it is standard practice to multiplex them.

Application of online redo logs

Dear all,
In my organisation recently standby database has been configured. Now my task is to restore a full online+redo backup which is created in primary database in the standby database. Once it is over I have to apply the newly created redo logs generated after the online backup.
I am planning to restore the online+redo backup using the following command
brrestore -b "BRBACKUP log file" -m full. Once it is done I have to apply the online redo logs. I am confused how to apply manually the newly created redo logs. Is there any document regarding it. I searched and found many information in net but nothing seems to be very convincing as this is a critical activity.
Best Regards,
Tapan

Hello Tapan,
> brrestore -b "BRBACKUP log file" -m full. Once it is done I have to apply the online redo logs.
Bad idea, you need a standby controlfile and not a backup controlfile on the standby site.
> I am confused how to apply manually the newly created redo logs. Is there any document regarding it.
You can do this manually by your own or by Oracle Dataguard.
I would suggest that you get a training on Oracle Dataguard and then you will understand the concepts and will be able to setup a DR solution. It makes not much sense to explain you all the steps and the functions, because of in a critical moment you should know what to do and why.
If you really want to try it by your own - so start with this:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/toc.htm
http://download.oracle.com/docs/cd/B19306_01/server.102/b14230/toc.htm
Regards
Stefan

Adding online redo logs with standby database in place

Hi group,
I have decided to add one new member to my existing redo log groups and an additional redo log group to my primary database.
That change went ok without problems. I assumed that with standby_file_management=auto the equivalent online redo logs are created on the standby database. But this is not the case.
The documentation is unclear about this point and I did not find anything suitable on metalink. The docs suggest to cancel managed recovery on the standy, setting standby_file_management to MANUAL and then adding online logs, quote:
"To add an online redo log, use a SQL statement such as this:
SQL> ALTER DATABASE ADD STANDBY LOGFILE 'prmy3.log' SIZE 100K;"
This however - IMO - adds a new STANDBY redo log to the standby database, what I need is an ONLINE redo log.
Does anybody have some experience to share here?
Facts:
Solaris 8
Oracle 9.2.0.6
Thanks!
Martin

OK, for those who come across the same problem.
You need to create a new standby controlfile, copy it as well as any new online redo log from production to the standby environment.
Once the files are in place, start the standby as normal and open it read only to see if everything is ok:
startup nomount
alter database mount standby database;
alter database open read only
Only when there are no errors in your alert.log you are safe.
Martin

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

Multiplexing Online redo logs, archive logs, and control files.

Currently I am only multiplexing my control files and online redo logs, My archive logs are only going to the FRA and then being backed up to tape.
We have to replace disks that hold the FRA data. HP says there is a chance we will have to rebuild the FRA.
As my archive logs are going to the FRA now, can I multiplex them to another disk group? And if all of the control files, online redo logs and archive logs are multiplexed to another disk group, when ASM dismounts the FRA disk group due to insufficient number of disks, will the database remain open and on line.
If so then I will just need to rebuild the ASM volumes, and the FRA disk group and bring it to the mount state, correct?
Thanks!

You can save your online redo logs and archive logs anywhere you want by making use of of init params create_online_log_dest and log_archive_dest_n. You will have to create new redo log groups in the new location and drop the ones in the FRA. The archive logs will simply land wherever you designate with log_archive_dest_n parameters. Moving the control files off FRA is a little trickier because you will need to restore your controlfile to a non-FRA destination and then shutdown your instance, edit the control file param to reflect changes and restart.
I think you will be happier if you move everything off the FRA diskgroup before dismounting it, and not expecting the db to automagically recover from the loss of files on the FRA.

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

Online redo logs

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