Impact of loss of Archived Logs

DB version:10gr2, 11g
Will RMAN backup job fail if there is a loss of an archived redo log? If so, what shoud the best approach be?

If the rman job included backing up archive logs, it certainly will fail in backing up the archive logs.
using channel ORA_SBT_TAPE_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 03/29/2010 02:55:53
RMAN-06059: expected archived log not found, lost of archived log compromises recoverability
ORA-19625: error identifying file /u01/oradata/dv14/arch/dv14_1_279_676731629.dbf
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3

Similar Messages

Recovery of database with loss of archived logs

Hi,
I tried restoring the database using the standard practice, however, I am encountering errors. It looks like we are missing archive log files, but I am not sure. Could anyone provide more insight to this problem and how to recover the database?
Here are the steps we did.
SVRMGR> connect internal
Connected.
SVRMGR> startup
ORACLE instance started.
Total System Global Area 1117552144 bytes
Fixed Size 48656 bytes
Variable Size 291995648 bytes
Database Buffers 819200000 bytes
Redo Buffers 6307840 bytes
Database mounted.
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
SVRMGR> recover database using backup controlfile until cancel;
ORA-00279: change 663652622 generated at 02/13/02 06:20:02 needed for thread 1
ORA-00289: suggestion : /oraclesw8_redolog/ARCHIVE_CP/infr/infr_1_13598.dbf
ORA-00280: change 663652622 for thread 1 is in sequence #13598
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
Log applied.
ORA-00279: change 663654936 generated at 02/13/02 07:04:14 needed for thread 1
ORA-00289: suggestion : /oraclesw8_redolog/ARCHIVE_CP/infr/infr_1_13599.dbf
ORA-00280: change 663654936 for thread 1 is in sequence #13599
ORA-00278: log file '/oraclesw8_redolog/ARCHIVE_CP/infr/infr_1_13598.dbf' no longer needed for this recovery
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
AUTO
ORA-00308: cannot open archived log '/oraclesw8_redolog/ARCHIVE_CP/infr/infr_1_13599.dbf'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01195: online backup of file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/oraclesw8_data00/oradata/infr/infr_system_01.dbf'

Hi
It looks like you may have to manually apply the last redo log.
SVRMGR> SELECT member FROM v$log l, v$logfile f WHERE l.group# = f.group# AND l.status = 'CURRENT';
Note the path of this log file.
SVRMGR> Recover database until cancel
When you get the message that you mentioned -
Apply the log member from the select statement above. Give it
the full path as it appears on the select statement.
SVRMGR> Alter database open resetlogs;
The system should respond with "Statement processed".
Good Luck,
Bob

Archive log loss

Hi,
Does any impact when we loss archived log file.
We take it by RMAN --> backup database plus archivelog
under what circumstance the loss of the file will affect us
Regards
Athil

Depends if you loss archivelog before current backup and yours current backup can be restored succesfully then you neednt to apply those archivelog ,while if yours archivelog after current backup get hole then you will be able to recover yours database till before that holed archivelog i.e if you have yesterday backup and you are going to have backup today at 9:00 PM but before having backup yours database crash say at 8:00 PM ,if you have alls archivelog before crash 8:00PM then you can apply yours restored yesterday backup archivelog till today before crash ,if one of them archivelog got corrupted say one archivelog sequence 900 get corrupted at 1:00 PM then you can only apply yesterdays database backup till 1:00 PM or till before sequence number 900 899.
Archivelog is crucial for backup strategy and always keep archivelog atleast two multiple locations.
Khurram

How to practice "Archived log sequences loss- Block corruptions recovery"

Hello,
Prepare and test a recovery scenarios
- System Tablespace loss
- Online Redolog loss
- Controlfile loss
- Data Tablespace loss
- Single/multiple datafile loss
- Archived log sequences loss- Block corruptions recovery
- Total loss (database)
- Total loss (server = database/software/parameter files)
11g on windows
I am practicing my rman recovery and found this list of recovery scenarios. I have completed all scenarios
besides "Archived log sequences loss- Block corruptions recovery"
How do I break the database for the snenario "Archived log sequences loss- Block corruptions recovery"?
Do I delete the acr.001 files in directory I:\oracle\product\11.1.0\db_1\RDBMS? Then recovery as far forward as I can?
thanks for your help.

thanks for the tips
11g on windows 2003
I broke the database like this:
rman backup
shutdown immediate;
deleted datafile 5
delete most recent archivelogs seq 5 and 6;
recovered like this:
startup mount;
restore datafile 5;
recover datafile 5;
alter database open;
This does not seem correct? Did this also apply my archivelogs seq 5 and 6? Should I also do a point in time recovery?
Should I also run this?
run (set until sequence 6 thread 1; restore database; recover database;)
thanks for any help

Data guard real time apply vs archived log apply on physical standby

Dear DBA's,
last week i configuared DR , now the phyiscal stanby database is archive apply mode,
i want to confirm is it better to apply the archived log or should i cahnge it to real time apply .
give me sugesstions.
Thanks and Regards
Raja...

One question are you using ARCH transport to move the redo? or have you configured standby redo logs and logwr transport (either async or syncronous), if you are using the archiver to transport the logs then you can not use real time apply.
If you are using log writer to transpor the redo the realtime apply reduces the recovery time required if you need to failover as trher should be less redo to apply to bring the standby up to date, which mode you use to transport redo will depend on what is acceptable in terms of data loss and the impact on performance.

How to recover the database when some of the archive log file get deleted.

I am facing a problem with Oracle database, which is related to archivelogs.
Our development database is running in archivelog mode, but we don't have backups scheduled and have no recovery catalog.
When the database was in running condition, disk got full, so some archivelogs were deleted manually.
After this they restarted the DB, and now DB is not coming up. Errors are as follows:
SQL> startup
ORACLE instance started.
Total System Global Area 1444383504 bytes
Fixed Size 731920 bytes
Variable Size 486539264 bytes
Database Buffers 956301312 bytes
Redo Buffers 811008 bytes
Database mounted.
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
SQL> alter database open resetlogs;
alter database open resetlogs
ERROR at line 1:
ORA-01113: file 1 needs media recovery
ORA-01110: data file 1: '/export/home/oracle/dev/ADVFRW/ADVFRW.system'
SQL> recover datafile '/export/home/oracle/dev/ADVFRW/ADVFRW.system'
ORA-00283: recovery session canceled due to errors
ORA-01610: recovery using the BACKUP CONTROLFILE option must be done
SQL> recover database using backup controlfile;
ORA-00279: change 215548705 generated at 09/02/2008 17:06:10 needed for thread
1
ORA-00289: suggestion :
/export/home/oracle/dev/ADVFRW/ADVFRW.archivelog1/LOG_ADVFRW_1107_1.ARC
ORA-00280: change 215548705 for thread 1 is in sequence #1107
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
/export/home/oracle/dev/ADVFRW/ADVFRW.archivelog1/LOG_ADVFRW_1107_1.ARC
ORA-00308: cannot open archived log
'/export/home/oracle/dev/ADVFRW/ADVFRW.archivelog1/LOG_ADVFRW_1107_1.ARC'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
CANCEL
Media recovery cancelled.
SQL>
1. How to recover the database and bring it online
Any help will be highly appreciated.
With Regards
Hemant Joshi
Edited by: hem_Kec on Sep 7, 2008 9:07 AM

Hi,
Archive log files are the copies of redolog files.As redo log files are circularly overwritten,oracle generates archive log file of the corresponding redo logfiles being overwritten.So if you have a backup that dates back to 10 am in the morning and if your database creashed at 3 pm,you cannot use the redo log files alone as they have incomplete information.To completely recover the database upto 3 pm,you need archive log files generated between 10 am to 3 pm. In your case since you are missing one archive log file,you cannot perform complete recovery and hence would suffer data loss.

Need a shell script to backup archive log daily

Hi All,
We need a shell script to backup the archive logs daily after shutting down the concurrent manager and once the backup is completed, needs to start the concurrent manager through the script itself, if you have any ideas or sample scripts, please provide and help us.
The objective is to backup the daily archive logs with out any loss of data.
Thanks,

I do not have a similar script to share, sorry. However, you may review the following links/notes:
Note: 137181.1 - RMAN Backup Shell Script Example
https://metalink2.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=137181.1
Recovery Manager (RMAN) Manuals
http://www.oracle.com/pls/db102/homepage

"recover database until cancel" asks for archive log file that do not exist

Hello,
Oracle Release : Oracle 10.2.0.2.0
Last week we performed, a restore and then an Oracle recovery using the recover database until cancel command. (we didn't use backup control files) .It worked fine and we able to restart the SAP instances. However, I still have questions about Oracle behaviour using this command.
First we restored, an online backup.
We tried to restart the database, but got ORA-01113,ORA-01110 errors :
sr3usr.data1 needed media recovery.
Then we performed the recovery :
According Oracel documentation, "recover database until cancel recovery" proceeds by prompting you with the suggested filenames of archived redo log files.
The probleme is it prompts for archive log file that do not exist.
As you can see below, it asked for SMAarch1_10420_610186861.dbf that has never been created. Therefore, I cancelled manually the recovery, and restarted the database. We never got the message "media recovery complete"
ORA-279 signalled during: ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10417_61018686
Fri Sep 7 14:09:45 2007
ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10418_610186861.dbf'
Fri Sep 7 14:09:45 2007
Media Recovery Log /oracle/SMA/oraarch/SMAarch1_10418_610186861.dbf
ORA-279 signalled during: ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10418_61018686
Fri Sep 7 14:10:03 2007
ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10419_610186861.dbf'
Fri Sep 7 14:10:03 2007
Media Recovery Log /oracle/SMA/oraarch/SMAarch1_10419_610186861.dbf
ORA-279 signalled during: ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10419_61018686
Fri Sep 7 14:10:13 2007
ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10420_610186861.dbf'
Fri Sep 7 14:10:13 2007
Media Recovery Log /oracle/SMA/oraarch/SMAarch1_10420_610186861.dbf
Errors with log /oracle/SMA/oraarch/SMAarch1_10420_610186861.dbf
ORA-308 signalled during: ALTER DATABASE RECOVER    LOGFILE '/oracle/SMA/oraarch/SMAarch1_10420_61018686
Fri Sep 7 14:15:19 2007
ALTER DATABASE RECOVER CANCEL
Fri Sep 7 14:15:20 2007
ORA-1013 signalled during: ALTER DATABASE RECOVER CANCEL ...
Fri Sep 7 14:15:40 2007
Shutting down instance: further logons disabled
When restaring the database we could see that, a recovery of online redo log has been performed automatically, is it the normal behaviour of a recovery using "recover database until cancel" command ?
Started redo application at
Thread 1: logseq 10416, block 482
Fri Sep 7 14:24:55 2007
Recovery of Online Redo Log: Thread 1 Group 4 Seq 10416 Reading mem 0
Mem# 0 errs 0: /oracle/SMA/origlogB/log_g14m1.dbf
Mem# 1 errs 0: /oracle/SMA/mirrlogB/log_g14m2.dbf
Fri Sep 7 14:24:55 2007
Completed redo application
Fri Sep 7 14:24:55 2007
Completed crash recovery at
Thread 1: logseq 10416, block 525, scn 105140074
0 data blocks read, 0 data blocks written, 43 redo blocks read
Thank you very much for your help.
Frod.

Hi,
Let me answer your query.
=======================
Your question: While performing the recovery, is it possible to locate which online redolog is needed, and then to apply the changes in these logs
1.   When you have current controlfile and need complete data (no data loss),
      then do not go for until cancel recovery.
2.   Oracle will apply all the redologs (including current redolog) while recovery
     process is    on.
3. During the recovery you need to have all the redologs which are listed in the    view    V$RECOVERY_LOG and all the unarchived and current redolog. By querying V$RECOVERY_LOG you    can find out about the redologs required.
4. If the required sequence is not there in the archive destination, and if recovery process    asks for that sequence you can query V$LOG to see whether requested sequence is part of the    online redologs. If yes you can mention the path of the online redolog to complete the recovery.
Hope this information helps.
Regards,
Madhukar

Question about only new archive logs backed up in backup

Hi,
We are taking daily two online backup. We are running database in ARCHIVELOG mode. We configure database in PRIMARY and PHYSICAL STANDBY mode. Till now, we were taking all archive logs in backup. But it was causing problem of lot of space utilization of disk.
So based on search in this forum, I am planning to take only new archive logs generated since last backed up using following command.
BACKUP ARCHIVELOG all not backed up 1 times format '$dir/archivelogs_%s_%t' FORCE;
I am not sure about how it impact during restore and recovery when we take only new archivelogs in backup.
We restore database and then after perform always incomplete recovery till latest SCN capture in backup using following commands.
RESTORE DATABASE;
RECOVER DATABASE UNTIL SCN $BACKUP_LAST_SCN;
Do you see any problem/risk of implementing this solution going ahead?
Please let me provide your thoughts/inputs for this.
Thanks.
Shardul

Hi,
We are not deleting archive logs from actual location after backup. We keep latest 6 days archive logs at actual location. But here we are planning to put only new archive logs in backup image which were not backed up due to disk size problem.
For your reference below is our datbase backup RMAN commands. We are taking full database backup.
run {
ALLOCATE CHANNEL C1 TYPE DISK;
delete noprompt archivelog all completed before 'sysdate-5';
SQL 'ALTER SYSTEM ARCHIVE LOG CURRENT';
BACKUP INCREMENTAL LEVEL=0 CUMULATIVE format '$dir/level0_%u' DATABASE include current controlfile
for standby force;
SQL 'ALTER SYSTEM ARCHIVE LOG CURRENT';
BACKUP ARCHIVELOG all not backed up 1 times format '$dir/archivelogs_%s_%t' FORCE;
BACKUP CURRENT CONTROLFILE format '$dir/control_primary' FORCE;
Then in this polich do you see any problem when we restore database as PRIMARY or PHYSICAL STANDBY on server. We are using Oracle 10.2.0.3.

Archive log filling up a gig per minute

Hi there,
No one is on the database amd every day now the archive log is filling up over a gig per minute so when I get in work in the morning the backup didn't run and the archive directory is full and the database is not available.
This has been happening for the last 6 days and I can't figure it out. I have to keep clearing out archive files to get the directory percentage down so a few users can run some reports.
This database is not growing at all. There is no data being added to it, its a histrical database for report running only.
Here is the file system, as you can see, big drive so I am at a loss.
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
3.1G 829M 2.2G 28% /
/dev/mapper/VolGroup00-LogVol_USR
4.0G 3.0G 813M 79% /usr
/dev/mapper/VolGroup00-LogVol_d01
160G 116G 36G 77% /d01
/dev/mapper/VolGroupBackup-LogVol_Backup
213G 195G 7.6G 97% /backup
/dev/sda1 99M 11M 84M 11% /boot
none 1.5G 0 1.5G 0% /dev/shm

user13286861 wrote:
Hi there,
No one is on the database amd every day now the archive log is filling up over a gig per minute so when I get in work in the morning the backup didn't run and the archive directory is full and the database is not available.
This has been happening for the last 6 days and I can't figure it out. I have to keep clearing out archive files to get the directory percentage down so a few users can run some reports.
This database is not growing at all. There is no data being added to it, its a histrical database for report running only.
Here is the file system, as you can see, big drive so I am at a loss.
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
3.1G 829M 2.2G 28% /
/dev/mapper/VolGroup00-LogVol_USR
4.0G 3.0G 813M 79% /usr
/dev/mapper/VolGroup00-LogVol_d01
160G 116G 36G 77% /d01
/dev/mapper/VolGroupBackup-LogVol_Backup
213G 195G 7.6G 97% /backup
/dev/sda1 99M 11M 84M 11% /boot
none 1.5G 0 1.5G 0% /dev/shmRun off a statspack report and post the "Instance Activity", "Top 5" and "Load Profile" sections here. Don't forget to use the "cost" tags to get the output in fixed font (see end of post).
Question 1 - what did you do 6 days ago ?
Question 2 - what method are you using for backups.
Guess 1 - you have a load of tablespaces in backup mode, and you're doing a lot of delayed block cleanout.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
To post code, statspack/AWR report, execution plans or trace files, start and end the section with the tag {noformat}{noformat} (lowercase, curly brackets, no spaces) so that the text appears in fixed format.
There is a +"Preview"+ tab at the top of the text entry panel. Use this to check what your message will look like before you post the message. If it looks a complete mess you're unlikely to get a response. (Click on the +"Plain text"+ tab if you want to edit the text to tidy it up.)

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.

When creating a tablespace why should we enable LOGGING when a database is already on ARCHIVE LOG mode

Question :
When creating a tablespace why should we enable LOGGING when a database is already on ARCHIVE LOG mode ?
Example:
Create Tablespace
CREATE SMALLFILE TABLESPACE "TEST_DATA"
LOGGING
DATAFILE '+DG_TEST_DATA_01(DATAFILE)' SIZE 10G
AUTOEXTEND ON NEXT 500K MAXSIZE 31000M
EXTENT MANAGEMENT LOCAL
SEGMENT SPACE MANAGEMENT AUTO;
LOGGING: Generate redo logs for creation of tables, indexes and partitions, and for subsequent inserts. Recoverable
Are they not logged and not recoverable if we do not enable LOGGING? What is that ARCHIVELOG mode does?

What is that ARCHIVELOG Mode Does?
Whenever your database is in archive log mode , Oracle will backup the redo log files in the form of Archives so that we can recover the database to the consistent state in case of any failure.
Archive logging is essential for production databases where the loss of a transaction might be fatal.
Why Logging?
Logging is safest method to ensure that all the changes made at the tablespace will be captured and available for recovery in the redo logs.
It is just the level at which we defines:
Force Logging at DB level
Logging at Tablespace Level
Logging at schema Level
Before the existence of FORCE LOGGING, Oracle provided logging and nologging options. These two options have higher precedence at the schema object level than the tablespace level; therefore, it was possible to override the logging settings at the tablespace level with nologging setting at schema object level.

DB Back to a Specific Time with Archive Logs (Until cancel or time?)

I'll try to be as clear as possible with my intended goals and the limitations of the system I'm working with:
1. We have a test instance of our Oracle DB that I would like to be able to refresh with data from the production instance at any time, without having to shut down the production database or put tablespaces into hot backup mode.
2. Both systems are HP Itanium boxes with differing numbers of CPUs and RAM. Those differences have been taken into account in the init.ora file for the DB instances.
3. The test and production instances are using a SAN to hold the following file systems: ora_redo1, ora_redo2, ora_archlog, oradata10g. The test instance is using SAN snapshots (HP EVA series SAN) of the production file systems to pull the data over when needed. The problem is that the only window to do this is when the production system is down for nightly maintenance which is about a 20 minute period. I want to escape this limitation.
What I've been doing is using the HP SAN to take snapshots of the file systems on the production system mentioned above. I do this while the production DB is up and running. I then import those snapshots into the test system, run an fsck to ensure file system integrity, then start up the Oracle instance as follows:
startup mount
Then I run the following query I found on line to determine the current redo log:
select member from v$logfile lf , v$log l where l.status='CURRENT' and lf.group#=l.group#;
Then I attempt to run a recovery as follows:
recover database using backup controlfile until cancel;
When prompted, I enter the path to the first of the current redo logs and hit enter. After waiting, sometimes it says that the recovery completed, other times it stops saying there was an error and that more files are needed to make the DB consistent.
I took the above route because doing a recover until time (which is what I really want to do) kept prompting me for the next archive log in sequence that didn't yet exist when I took the SAN snapshot. Here was my recover until time command:
recover database until time 'yyyy-mm-dd:hh:mm:ss' using backup controlfile;
What I would like to do is take the SAN snapshot and then recover the database to about a minute before the snapshot using the archive logs. I don't want to use RMAN since that seems to be overkill for this purpose. A simple recovery to a specific point in time seems to be all that is needed and I have archive logs which, I assume, SHOULD help me get there. Even if I have to lose the last hour's worth of transactions I could live with that. But my tests setting the specific time of recovery to even 12 hours earlier still resulted in a prompt for the next, non-existent archivelog.
I will also note that I even tried copying the next archive log over once it did exist and the recovery would then prompt me for the next archive log! I will admit right now that I really don't know a whole lot about Oracle or DBs, but it's my task to try and make it possible to "refresh" the test DB with the most recent data with no impact on the production DB.
The reason I don't want to use hot backup mode is that I don't know the DB schema other than there are probably 58 or more tablespaces. The goal is to use SAN snapshots for their speed instead of having to take RMAN files and copy them to the test instance. I'm sure I'm not the only person who has ever tried this. But most of what I've found on line refers to RMAN, hot backup mode, or down time. The first two don't take advantage of SAN snapshots for a quick swap of all the Oracle file systems and I can't afford downtime other than that window at night. Is there some reason that the recover to time didn't work even though I have archive logs?
One final point. The recover until cancel actually worked a couple of times, but it seems to be sporadic. It likely has something to do with what was happening on the production DB when I created the SAN snapshots. I actually thought I had a solution with recover until cancel last week until it didn't work three times in a row.

I haven't completely discounted it but it seems like I would need to back up to files, then restore from files. I don't want to do that. I want a full file system level SAN snapshot that I can just drop into place. The does work when the production base is shut down. However, considering that I do have archive logs, shouldn't it be possible to use them to recover to a specific scene without having to do an RMAN backup at all? It seems that doing an RMAN backup/recovery would just make this whole process a lot longer since the DB is 160 gigs in size (not huge, but the dump would take more time than I would like). With a SAN snapshot, if I can get this to work, I'm looking at about a 15-20 minute period of time to move the production DB over to test.
Since you are suggesting that RMAN may be a better approach I'll provide more details about what I'm trying to do. Essentially this is like trying to recover a DB from a server that had its power plug pulled. I was hoping that Oracle's automatic recovery would do the same thing it would do in that instance. But obviously that doesn't work. What I want to do is bring over all the datafiles, redo logs, and archive logs using the SAN snapshot. Then if possible use some aspect of Oracle (RMAN if it can do it) to mount the database, then recover to a specific time or SCN if using RMAN. However, when I tried using RMAN to do it, I got an error saying that it couldn't restore the data file because it already existed. Since I don't want to start from scratch and have RMAN rebuild files that I've already taken snapshots of (needless copying of data), I gave up on the RMAN approach. But, if you know of a way to use RMAN so that it can recover to a specific incarnation without needing to runm a backup first, I am completely open to trying it.

Recovery in Archive log

Hi,
how to recover from the loss of datafile if the DB is running in archive log mode...
Please some one give the steps...
Thanks & Regards..

how to recover from the loss of datafile if the DB is running in archive log mode...Just running archive log mode is not satisfy.Do you have backup of this datafile if yes then issue RESTORE DATAFILE <DATA FILE NO>;RECOVER DATAFILE <DATA FILE NO> or if you use user managed backup then restore that backup and issue RECOVER DATAFILE <DATA FILE NO> through sqlplus.But if you do not have backup of this dataflile then thare rest one way also(if your datafile created after creating control file),you can ALTER DATABASE CREATE DATAFILE 'FILE PATH ' AS 'FILE PATH ' and issue RECOVER DATAFILE 'FILE PATH ' through sqlplus.

Recoevery in Archive Log Mode

If our database is running in Archivelog mode and if instance crashes, then how we can oerfrom the recoevery process in order to recover the lost transactions which were never committed.
Thanks

Hi,
The crash recovery process is a special form of recovery, which happens the first time an Oracle database instance is started after a crash (or SHUTDOWN ABORT). In crash recovery, the goal is to bring the datafiles to a transaction-consistent state, preserving all committed changes up to the point when the instance failed.
Unlike the forms of recovery performed manually after a data loss, crash recovery uses only the online redo log files and current online datafiles, as left on disk after the instance failure. Archived logs are never used during crash recovery, and datafiles are never restored from backup.
The database applies any pending updates in the online redo logs to the online datafiles of your database. The result is that, whenever the database is restarted after a crash, the datafiles reflect all committed changes up to the moment when the failure occurred. (After the database opens, any changes that were part of uncommitted transactions at the time of the crash are rolled back.)
Instance Recovery is only used in a RAC environment. It is the application of online redo log by one instance that detected the crash of another instance.
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