Is it possible to use Archive Redo log file
Hi friends,
My database is runing in archive log mode.I had taken cold backup on Sunday but i am taking archive log file daily evening.
Wednesday my database crash that means i lost all control file,redo log file,datafile etc.
I have archived log file backup till Tuesday Night and other files like control file,datafile etc of Sunday .
1)Is it possible to recover database till tuesday if yes HOW to use archive log file.
(See SCN no of control file and datafiles is same ,if we use RECOVER DATABASE command oracle shows that media recovery is not requide.)
we don't have current control file we had lost in media crash.
null
Dear friend
In this scenario
you lost the contorl file
1>If you have old copy of Contorl file,
which has the current structure of the
database and all the archive files then
you can recover the database with
Ponint in time recovery (Using Backup Controlfile)
suresh
Similar Messages
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Hoping for a quick response : EXP and Archived REDO log files
I apologize in advance if this question has been asked and answered 100 times. I admit I didn't search, I don't have time. I'm leaving on vacation tomorrow, and I need to know if I'm correct about something to do with backup / restore.
we have 10g R2 running a single instance on a single server. The application vendor has "embedded" oracle with their application. The vendor's backup is a batch file using EXP - thus:
exp system/xpwdxx@db full=y file=D:\Orant\admin\db\EXP\db_full.dmp log=D:\Orant\admin\db\EXP\db_full.txt direct=y compress=y
This command is executed nightly at midnight. The files are then backed up by our nightly backup to offsite storage media.
Te database is running in autoarchive mode. The problem is, the archived redo files filled the drive they were being stored on, and it is the drive the database is on. I used OS commands to move 136G of archived redo logs onto other storage media to free the drive.
My question: Since the EXP runs at midnight, when there is likely NO activity, do I need to run in AutoArchive Mode? From what I have read, you cannot even apply archived redo log files to this type of backup strategy (IMP) Is that true? We are ok losing changes since our last EXP. I have read a lot of stuff about restoring consistent vs. inconsistent, and just need to know: If my disk fails, and I have to start with a clean install of Oracle and nothing else, can I IMP this EXP and get back up and running as of the last EXP? Or do I need the autoarchived redo log files back to July 2009 (136G of them).
Hoping for a quick response
Best Regards, and thanks in advance
Bruce DavisBruce Davis wrote:
Amardeep Sidhu
Thank you for your quick reply. I am reading in the other responses that since I am using EXP without consistent=y, I might not even have a backup. The application vendor said that with this dmp file they can restore us to the most recent backup. I don't really care for this strategy as it is untested. I asked them to verify that they could restore us and they said they tested the dmp file and it was OK.
Thank you for taking the time to reply.
Best Regards
BruceThe dump file is probably ok in the sense it is not corrupted and can be used in an imp operation. That doesn't mean the data in it is transactionally consistent. And to use it at all, you have to have a database up and running. If the database is physically corrupted, you'll have to rebuild a new database from scratch before you can even think about using your dmp file.
Vendors never understand databases. I once had a vendor tell me that Oracle's performance would be intolerable if there were more than 5 concurrent connections. Well, maybe in HIS product ..... Discussions terminated quickly after he made that statement. -
Recover Database is taking more time for first archived redo log file
Hai,
Environment Used :
Hardware : IBM p570 machine with P6 processor Lpar of .5 CPU and 2.5 GB Ram
OS : AIX 5.3 ML 07
Cluster: HACMP 5.4.1.2
Oracle Version: 9.2.0.4 RAC
SAN : DS8100 from IBM
I have used flash copy option to copy the database from production to test machine. Then tried to recover the database to an consistent state using the command "recover automatic database until cancel". System is taking long time and after viewing the alert log it was found that, for the first time, if it is reading all the datafiles and it is taking 3 seconds for each datafile. Since i have more than 500 datafiles, it is nearly taking 25 mins for applying the first archived redo log file. All other log files are applied immeidately without any delay. Any suggession to improve the speed will be highly appreciated.
Regards
SridharAfter chaning the LPAR settings with 2 CPU and 5GB RAM, the problem solved.
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Delete old and unused Archived Redo Log Files
Hello forum!
My db was in ARCHIVELOG mode and It created 9GB of archived redo log files.
Now I put the db in NOARCHIVELOG mode, can I delete all the ARLF? am I sure that the DB never need those files in the future?
If yes, how can I delete them? I will use 'del' operative system command?
In addition, I found this command:
SQL>alter database open resetlogs;
is it useful for my purpose?
thank you!You are safe to remove those archivelog files if you altered your database to no archive log mode. Just remove them from OS level
Please bear in mind that database in no archivelog mode will lost data in the event of disaster.
SQL>alter database open resetlogs;Doesn't help in your situation, it's use to bring up database after incomplete recovery. -
Select from .. as of - using archived redo logs - 10g
Hi,
I was under the impression I could issue a "Select from .. as of" statement back in time if I have the archived redo logs.
I've been searching for a while and cant find an answer.
My undo_management=AUTO, database is 10.2.0.1, the retention is the default of 900 seconds as I've never changed it.
I want to query a table as of 24 hours ago so I have all the archived redo logs from the last 48 hours in the correct directory
When is issue the following query
select * from supplier_codes AS OF TIMESTAMP
TO_TIMESTAMP('2009-08-11 10:01:00', 'YYYY-MM-DD HH24:MI:SS')
I get a snapshot to old ORA-01555 error. I guess that is because my retention is only 900 seconds but I thought the database should query the archive redo logs or have I got that totally wrong?!
My undo tablespace is set to AUTOEXTEND ON and MAXSIZE UNLIMITED so there should be no space issues
Any help would be greatly appreciated!
Thanks
RobertIf you want to go back 24 hours, you need to undo the changes...
See e.g. the app dev guide - fundamentals, chapter on Flashback features: [doc search|http://www.oracle.com/pls/db102/ranked?word=flashback&remark=federated_search]. -
Use of standby redo log files in primary database
Hi All,
What is the exact use of setting up standby redo log files in the primary database on a data guard setup?
any good documents?A standby redo log is required for the maximum protection and maximum availability modes and the LGWR ASYNC transport mode is recommended for all databases. Data Guard can recover and apply more redo data from a standby redo log than from archived redo log files alone.
You should plan the standby redo log configuration and create all required log groups and group members when you create the standby database. For increased availability, consider multiplexing the standby redo log files, similar to the way that online redo log files are multiplexed.
refer the link,and Perform the following steps to configure the standby redo log.:-
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ps.htm#i1225703
If the real-time apply feature is enabled, log apply services can apply redo data as it is received, without waiting for the current standby redo log file to be archived. This results in faster switchover and failover times because the standby redo log files have been applied already to the standby database by the time the failover or switchover begins.
refer the link
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/log_apply.htm#i1023371 -
Good Morning to all ;
I am getting bit confused from oracle official link . REF_LINK : Log Apply Services
Redo data transmitted from the primary database is received by the RFS on the standby system ,
where the RFS process writes the redo data to either archived redo log files or standby redo log files.
In standby site , does rfs write redo data in any one file or both ?
Thanks in advance ..Hi GTS,
GTS (DBA) wrote:
Primary & standby log file size should be same - this is okay.
1) what are trying to disclose about largest & smallest here ? - You are confusing.
Read: http://docs.oracle.com/cd/E11882_01/server.112/e25608/log_transport.htm#SBYDB4752
"Each standby redo log file must be at least as large as the largest redo log file in the redo log of the redo source database. For administrative ease, Oracle recommends that all redo log files in the redo log at the redo source database and the standby redo log at a redo transport destination be of the same size."
GTS (DBA) wrote:
2) what abt group members ? should be same as primary or need to add some members additionally. ?
Data Guard best practice for performance, is to create one member per each group in standby DB. on standby DB, one member per group is reasonable enough. why? to avoid write penalty; writing to more than one log files at the standby DB.
SCENARIO 1: if in your source primary DB you have 2 log member per group, in standby DB you can have 1 member per group, additionally create an extra group.
primary
standby
Member per group
2
1
Number of log group
4
5
SCENARIO 2: you can also have this scenario 2 but i will not encourage it
primary
standby
Member per group
2
2
Number of log group
4
5
GTS (DBA) wrote:
All standby redo logs of the correct size have not yet been archived.
- at this situation , can we force on standby site ? any possibilities ?
you can not force it , just size your standby redo files correctly and make sure you don not have network failure that will cause redo gap.
hope there is clarity now
Tobi -
Hi,
Can anyone tell me what's the real difference between a backup file and a redo log file/archived redo log file and the scenarios (examples) when each of them can be used (for example, "......") ? Both are used for database/instance recovery. I have read the concepts of there 2 terms, but I need some additional information about the difference.
Thanks!Roger25 wrote:
What i still don't understand is how redo mechanism works; I know, redo logs records changes made to the database and it's used to re-do informations in case of a system failure/crash, for example. Ok, let's say I have a huge update, but when the system crash has occured, the transaction is neither comitted, nor rolled back. Then, how this redo is useful? If a system crash occur, all those updates aren't rolled back automatically? So the database state is as before executing that huge update? So in this case, 'what to redo'?No, with the system's crash, the transaction never gets a chance to get committed (and even rolled back) because a commit is only supposed to happen if there is an explicit or implicit commit statement is issued. Now, for the redo , with the statement, a commit marker is entered at the end of the redo stream of that transaction denoting that it's finally over now and for the corresponding transaction, the status is cleared from the transaction table that's stored in the Undo segment in which the Undo information of that transaction is stored. If you have given a huge update, the redo would be very highly required as you should be knowing that it's not all the time that the dirty buffers that are written to the data files unlikely the redo log files which are written every 3 econds. This means, there is a very fair chance that many changes have yet not even propagated to the data files for which the change vectors are now already there in the redo log files. Now, for the sake of clarity, assume that this transaction was actually committed! So now, without those changes be applied to the data files how Oracle can actually show the committed reults when the database next time would be opened? For this purpose, the redo change vectors are required. And for the uncommitted transactions , the applcation of the redo change vectors would keep on updating the Checkpoint numbers of the data files and would eventually get them synched with the control file and redo log files, without which the database would never be opened.
HTH
Aman.... -
Purpose of ONLINE REDO LOG FILES - Media or Instance recovery or BOTH ?
Hi
Currently studying this topic for the 1z0-031 exam and am a little confused.
my books (from instructor led class) say
-redo logs are a mean to provide redo transactions in the event of a DATABASE recovery
-redo log buffer gets flushed to redo log files to provide a recovery mechanism in case of MEDIA FAILURE
Then it says
-Online redo log files are used in a situation such as an INSTANCE FAILURE to recover uncommitted data which has not yet been written to the data files
- online redo log files are used for RECOVERY only.
Am i misunderstanding? Or are redo log files for both MEDIA and INSTANCE recovery? Or just INSTANCE ?
confused....
AmanjitOnline Redo Log Files are used in a sense for both Media and Instance Recovery. If your database is in NoArchive Mode then you will only be able to use the Redo Log Files for instance recover. But if you are running in Archive Log Mode then Redo Log Files are archived and will allow you to recover from media failure.
-
What is the purpose of standby redo log files
Hi,
What is the purpose of the standby redo log files in DR?
what if the standby redo log files are created? or else not created?
Please explain
Thanks3.1.3 Configure a Standby Redo LogA standby redo log is required for the maximum protection and maximum availability modes and the LGWR ASYNC transport mode is recommended for all databases. Data Guard can recover and apply more redo data from a standby redo log than from archived redo log files alone.
You should plan the standby redo log configuration and create all required log groups and group members when you create the standby database. For increased availability, consider multiplexing the standby redo log files, similar to the way that online redo log files are multiplexed.>
Reference http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ps.htm#i1225703
HTH
Anand -
Oracle 10g R2 Database Redo Log Files
I had 3 redo log files, each of size 50 MB. i added 3 more redo log files, each of size 250 MB.
Database is running in archive mode, files are generating with different sizes like 44 MB and 240 MB, i need to know is this harm for database or not?
to make all archive redo log files generation of equal size what should i do?
Please guideWaheed,
When the redo log switch willbe happening,oracle would be asking archiver to log that into the archive file.So in case you have any parameters set to make the switch happen at certain time,depending on the activity of teh database,the archive file size may vary.There is no harm wit the different sizes of the files.What matters is the transaction informaiton contained in them not their size.
to make all archive redo log files generation of equal size what should i do?
As mentioned by Syed, you can make the switch happen at a defined interval which will not ensure but still will be a step to make the archive files of the same size.But I shall say you should bother more about making sure that the files are available rather than their size.
Aman.... -
Manual archiving of redo log files....
Hi ,
If the database is running in NOARCHIVELOG mode , is it possible to archive the redo log files manually.... and how..????
Note: I use Oracle 10g v.2
Many thanks,
SimonHaving issued the command , i noticed that the USE_DB_RECOVERY_FILE_DEST is the destination of LOG_ARCHIVE_DEST_10:
SQL> select dest_id,dest_name,status,destination from V$ARCHIVE_DEST;
DEST_ID DEST_NAME STATUS DESTINATION
1 LOG_ARCHIVE_DEST_1 VALID C:\oracle\product\10.2.0\flash_recovery_area\EPESY\ARCHIVELOG\
2 LOG_ARCHIVE_DEST_2 INACTIVE
3 LOG_ARCHIVE_DEST_3 INACTIVE
4 LOG_ARCHIVE_DEST_4 INACTIVE
5 LOG_ARCHIVE_DEST_5 INACTIVE
6 LOG_ARCHIVE_DEST_6 INACTIVE
7 LOG_ARCHIVE_DEST_7 INACTIVE
8 LOG_ARCHIVE_DEST_8 INACTIVE
9 LOG_ARCHIVE_DEST_9 INACTIVE
10 LOG_ARCHIVE_DEST_10 VALID USE_DB_RECOVERY_FILE_DESTBut... i have set the LOG_ARCHIVE_DEST parameter not ...._10.
How the system will point to the directory i've set in my previous alter system command...- when i use the archive log list???
Many thanks,
Simon -
How could I find specified date of REDO log and archive REDO log ?
we use Oracle11gr2 on win2008R2.
1
How could I find specified date of REDO log(2013/10/17,etc) and archive REDO log ?
2
What is the format of archive REDO log.? (zipped file ?)user12075536123 wrote:
1)
select * from v$archived_log;
select * from v$log_history;
but there is a possibility there is no old data
below contains no filename column
SQL> desc v$log_history
Name Null? Type
RECID NUMBER
STAMP NUMBER
THREAD# NUMBER
SEQUENCE# NUMBER
FIRST_CHANGE# NUMBER
FIRST_TIME DATE
NEXT_CHANGE# NUMBER
RESETLOGS_CHANGE# NUMBER
RESETLOGS_TIME DATE
there is NO data when archive mode is disabled -
Hi all,
Is there any way to migrate existing archived redo logs to the ASM diskgroup?
Regards,
Vijayaraghavan KThanks..
I have copied the spfile from the last backup to the asmdiskgroup by using below command
RESTORE SPFILE TO '+DATA/spfilesid.ora';
When i try to start the database it is picking the spfile from file system alone. It is possible to rmap the spfile to the diskgroup?
Regards,
Vijayarghavan K -
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
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