Need Instance Recovery?

I have a very strange situation right now:
1) Turn on Archive log Mode
2) Everything works fine ( both database & oracle apps)
3) Weekly full backup successful
4) Daily backup successful
5) Oracle databas hangs (shutdown & startup the database, same problem)
6) Turn off Archive log Mode
7) delete all archive logs
8) Everything works fine ( both database & oracle apps)
9) Try to turn on Archive log Mode again.
Failure: with message need to instance recovery???? How come it is? The Archive Log Mode is off and the database and oracle application works fine.
Any ideas? Or how to fix it?
FAN
Message was edited by:
user623471

Without really knowing the time gap and transaction volumes (ie archivelog rates) at these steps, and the exact message ...... possibly speculating ....
but I think that the most likely cause is that the ArchiveLog Destination filesystem is out of space for new archivelogs. That would cause
a. The "hang" at step 5 {because Oracle can't archive the active/current redolog}
b. The "hang" at startup in step 5 {because Oracle *still* cant archive ...}

Similar Messages

Instance recovery needed

hi pls help me
while iam changing NOARCHIVELOG to ARCHIVELOG
iam getting at startup mount INSTANCE RECOVERY IS NEEDED
what should i do?
thank you

How did you make the database to archivelog mode?
SQL> CONNECT sys AS SYSDBA
SQL> STARTUP MOUNT;
SQL> ALTER DATABASE NOARCHIVELOG;
SQL> ALTER DATABASE OPEN;
or
Go to init parameter file
Set Archivelog parameters
log_archive_start=True
log_archive_format=%S.arc
log_Archive_dest=<Path for Archive log>
SQL> shutdown;
SQL> startup mount;
SQL> alter database archivelog;
SQL> alter database open;
SQL> select log_mode from v$database;
Thanks,
Cherrish

Undo behavior during instance recovery

i'm confused about 2 concepts in applying undoin the case of instance failure
1.the common concepts of instance recovery which states :
a) when instance crash, oracle automatically applies all redo in the redo file to roll the db forward to the last scn be4 the failure
b) & redo data also contains the undo data, it also undo the uncommitted changes from the old valuesin the undo.
that'sok
2.but refereing to 10g database concepts (ch17 high availability-p317 if pdf)
url: http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14220/high_av.htm#sthref2531
it says:
With fast-start fault recovery, the Oracle database is opened for access by applications without having to wait for the undo, or rollback, phase to be completed.
The rollback of data locked by uncommitted transaction is done dynamically on an as needed basis.
If the user process encounters a row locked by a crashed transaction, then it just rolls back that row.
The impact of rolling back the rows requested by a query is negligible.
Fast-start fault recovery is very fast, because undo data is stored in the database, not in the log files.
Undoing a block does not require an expensive sequential scan of a log file.
so which situation is applicable in case of instance recovery
& do the undo behvior stated above in case of fast start fault recovery is an option or that's the default
thnx alot

Hi,
Whatever changes are made to the database, are recorded in redo log buffer cache sequentially and then shifted to redo log files. Suppose redo logs recorded following changes in the database in following sequence.
insert a row
update a row
commit;
delete a row
Now Instance crashes before these changes were written into the database (data remains in buffer cache until checkpoint)
Now during instance recovery, data which was still in buffer cache and not written to the data files, will be applied in same sequence. All undo data for update/delete is in redo log files and will be applied in the same sequence.
Salman

Oracle Concepts: Clarity required on Instance Recovery

One of my colleague was discussing instance recovery with me.
We discussed about checkpoint position, instance recovery phases (rolling forward & rolling back ), then he asked me whats the point of rolling forward (applying redo logs) and then rolling back (applying undo blocks), why not applying only committed transactions?
I told him that this happens because:
1) roll forward to recreate the scenario just before when Instance crashed
2) roll forward/roll back is the fastest way to recover
I am not sure from where I got this learning, may be some blog or article (probably not from Oracle Docs), but is it correct?
Regards,
Ankit Rathi

OnB wrote:
The 2nd point is completely wrong!Let me elaborate the context of 2nd point, it was mentioned in context of applying only committed transactions during recovery. As all the change vectors go in the redo log files, had there been any mechanism to identify only committed transactions, it would have taken more time (its really hypothetical as there is no mechanism exists, right?) by that mechanism to identify committted transactions (from redo logs) than simply rolling forward and rolling back.There is no context in that point, it's wrong , plain and simple!
There is a mechanism to identify committed transactions and that's called commit . But when you are doing recovery, you are not recovering just the committed transactions but you are recreating the entire scene before the crash which means, you would be required to apply both the uncommitted and committed work/change vectors. Going by your logic, if Oracle would start searching for the committed transactions, it would have many issues. One, time taken would be more higher. Two, there may be an instance that the commit was issued but before the commit complete message could reach the user, instance got terminated so how about those blocks which may be now in data file and have got an active transaction status and are unsure whether they are committed or not. And last, the way LGWR writes is just to keep on pushing change vectors to the redo stream in the order of the SCN. So for doing a recovery, you would need to reapply all of that changed data in that same SCN ordering.
The meaning of instance recovery is that you are not having a physical file crashed or deleted but there was a memory loss and few buffers were left out from being written to the data files and now, data files , control file and log files are not in synch.
The second point, where you are saying its the fastest, is wrong because even for the instance recovery , it can take a very long time and it would depend on how much work was left over before the instance was crashed. Roll Forward is the way to bring the data files in synch with the redo log files and the control files. So if the data files were on Checkpoint Number 100 and the control files and redo log files recorded the number as 120, the missing 20 numbers gap would be reentered in the data files because only then, the database would be opened. Now, your friend's question that why not only committed transaction because you never say a transaction is only done when there is a commit. Whenever any DML is encountered , it's going to cause a transaction. And you do want that missing work to be recreated to ensure that if there was a commit issued before the instance was crashed , next time, Oracle would ensure that work is there and if not , it would be rolled back. And most importantly, in the redo log files all the change vectors go, not just for the committed transactions .This is fine, same understanding here.
Bring in your own thoughts now that how much you understood from this explanation before I start to get into more technical terms.I would like to know your view about the 1st point. Suppose, something went wrong (in terms of transactions) due to which instance crashed, if it rolls forward (as it happens automatically) during next start-up, will it crash again?
It would be rolled back in the case of the instance (next) startup. If all what you are doing is plain DML's they won't crash the instance as long as you haven't encountered any bug in the case of which, next time also the instance may crash.
Aman....

Need Instance level failover in Windows Azure

Hi,
I have windows azure and sql server 2008 r2. I need to incorporate instance level failover (like widows failover cluster). How do i configure failover cluster in windows azure.
Please dont recommend as Always on. since it has only DB level failover. But i need instance level failover. Please recommend if there is any other alternatives other than windows cluster failover.
Thanks,
Saravanan
Please vote if you find this posting was helpful or Mark it as answered.

Hi Durai,
According to your description, since the issue regards Windows Azure SQL Database. I will help you post the question in the Windows Azure SQL Database forums at
http://social.msdn.microsoft.com/Forums/en-US/home?forum=ssdsgetstarted. It is appropriate and more experts will assist you.
We need to verify if you install SQL Server in the Windows Azure Virtual Machines, and the High Availability and Disaster Recovery (HADR) solutions for SQL Server in Windows Azure Virtual Machines include AlwaysOn availability
groups ,database mirroring ,log shipping , and backup and restore with Windows Azure Blob Storage Service.
Most SQL Server features are supported on Windows Azure Virtual Machine with some exceptions.
However, SQL Server Failover Clustering is not supported.
For more information, see:
http://support.microsoft.com/kb/2721672/en-us
Regards,
Sofiya Li
Sofiya Li
TechNet Community Support

Undo tablespace and instance recovery

Is UNDO tablespace is mandatory during instance recovery. ?
Suppose my undo tablespace has some active transaction and instance crashes making undo tablespace inaccessible.
Will database search for that undo tablespace during startup or I can simply create a new one and set as new undo tablespace ?
With Regards
Amt

Hi,
>>I am actually confused
Keep in mind that If an Oracle instance crashes, any changes that are made in the SGA are not written to the data files. When you restart the instance, the SMON background process automatically performs instance recovery by performing the following tasks:
• Rolling forward changes that are made in the online redo log files but not in the data files. Since all the committed transactions are written to the online redo log files, these are successfully recovered as result of rolling forward changes from the online redo log files to the data files.
• Opening the database. After the database is opened, users can log on and access any data that is not locked by un-recovered transaction.
• Rolling back all the uncommitted transactions.
In resume, during database recovery, undo records are used to undo any uncommitted changes applied from the redo log to the datafiles.
But if your UNDO tablespace crashed, then you will need recover it, using steps like
1) shutdown abort (If the instance yet is up)
2) cp -a /backup/undo01.dbf /u01/oradata (restore the latest recent backup file)
3) startup mount
4) recover database or recover datafile '/u01/oradata/undo01.dbf'
5) alter database open;
In some cases, re-create it, also resolve the problem:
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:5669213349582
Missing UNDO tablespace in restore backup
>>I checked in test setup and it is actually waiting for missing UNDO tablespace.
Which exactly test you are doing?
Cheers

Crash recovery/ instance recovery

Hi,
How do oracle identifies crash recovery/ instance recovery
is required?
Regards,
Mathew

Hi,
>>But how do oracle identifies dabase is abnormally down and crash recovery is required?
I think that the checkpoint information that is desynchronized in redo log files and datafiles. It is necessary understand what is a checkpoint and what the CKPT process do. A checkpoint is a moment in time when all the changes (dirty blocks) made in the database buffer cache are made to the data files. The checkpoint is performed by the CKPT process and it creates an entry in the control file to identify the point in the online redo log file from where the instance recovery should begin in case of an instance failure. One of the ways a checkpoint is initiated is by the data block writer (DBWR) process. The DBWR process initiates a checkpoint by writing all modified data blocks in the data buffers (dirty buffers) to the data files. After a checkpoint is performed, all committed transactions are written to the data files. If the instance were to crash at this point, only new transactions that occurred after this checkpoint would need to be applied to the database to enable a complete recovery. Therefore, the checkpoint process determines which transactions from the redo logs need to be applied to the database in the event of a failure and subsequent recovery.
Cheers

Need a Recovery CD for HP Pavilion dv6t-7000, want to purchase the cd from south america

Hi there:
I accidentally deleted all partitions from my HP Pavilion dv6t-7000 hard disk, I need the recovery disk, where can I purchase and download it?

If you know someone in the USA... order the discs or have them order the discs and send to their address. Once they receive the discs, have them mail the disc set to you in Venezuela.
Alternatively, if you can still read the 25-digit Windows product key on the Microsoft COA affixed to the bottom the computer, you can install Windows 7 using this key. Please see "How to Install Windows 7 Without the Disc" for instructions on how to download Windows 7, create the installation media, and install Windows 7 using the 25-digit product key from the Microsoft COA on your computer. Using this method will not install any HP customizations or value-added software and you will have to manually install all needed drivers.
If you have any further questions, please don't hesitate to ask.
Please click the white KUDOS star to show your appreciation
Frank
{------------ Please click the "White Kudos" Thumbs Up to say THANKS for helping.
Please click the "Accept As Solution" on my post, if my assistance has solved your issue. ------------V
This is a user supported forum. I am a volunteer and I don't work for HP.
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HP p6787c - Windows 7, 8GB RAM, NVIDIA GT 240

Hard Drive Failure on HP DV 6000 Pavilion laptop Windows-XPsp3 OS - Need Data Recovery Help

Hard Drive Failure on HP DV 6000 Pavilion laptop - Need Data Recovery Help
HP Pavilion DV 6108 NR, RG365UA, purchased in late 2006 at Best Buy, with Windows XP, upgraded to Service Pack 3. It has a Fujitsu hard disk, 60 gigabyte, partitioned into C: and a Recovery D:.
Windows tries to boot up, but goes to blue screen with the message: "Unmountable Boot Volume" for one second, then just keeps recycling until I force a shutdown.
BIOS Phoenix, hard drive test result: " #1-08 Fail "
I ran a disk analysis/recovery program on the Cdrive and it seemed to show the directory structure intact, and it was able to recover some files. I was using the free one from Seagate (which only recovers small files). The second pass didn't run so well, and during the third run the program said I should not proceed further, and I should contact a professional disk recovery company.
However, the D drive seems to be intact, so, I wonder if the disk is corrupted or just some aspect of the logical C drive is bad.
How can I get the D: to run the recovery software on it? The recovery disks, made by Best Buy, only proceed to the R / F / Q option screen, and when I press R, I get a blue screen every time.
Tapping the F10 key during startup gets me nowhere. Ditto the F11 key.
I dont care about the hard disk; it is the data (files, docs, images, etc) that I want.
I contacted HP to order recovery disks but they are no longer available for my computer.
Any suggestions would be greatly appreciated!
Jon
This question was solved.
View Solution.

Update...
I found a website that offers the following:
http://www.computersurgeons.com/p-13442-recovery-kit-435422-001-for-hp-model-number-dv6108nr.aspx
Recovery Kit 435422-001 For HP Model Number dv6108nr
Price: $27.00
Recovery Kit Set (An Entire Image of the Computer hard drive when the computer was new)
But I wonder how useful it would be. Early XP , no doubt. And if my hard disk problem is a mechanical fault, would any recovery disk even work? The disks made by Best Buy when I bought mine new in 2006 don't do anything more than go to the R /F/ Q screen and then goes to a blue screen when I press R (to recover the OS and apps and data files). And, as I wrote, it is the data that I want, not the disk drive.

"needs media recovery" after a successful recovery ???

RMAN novice here....
Oracle 9.2.0.1.0 on Redhat Linux (Itanium)
Running in NOarchivelog mode
In RMAN, I backed up a set of datafiles in read only mode taking this approach....
sql "alter tablespace foo read only";
configure channel 1 device type disk format 'backupdisk/mybackuparea/foo.dbf.bck';
backup datafile 'dbdisk/mydb/foo.dbf';
sql "alter tablespace foo read write;
Everything seemed to go fine.
After some time, I wanted to restore/recover. This is what I did (again, in RMAN"...
sql "alter fablespace foo offline";
restore datafile 'dbdisk/mydb/foo.dbf';
recover datafile 'dbdisk/mydb/foo.dbf' noredo;
sql "alter tablespace foo online";
My first stab at it, without the "noredo" failed. But with the "noredo" I got
"Starting recover at ...."
A set of channel assignment statements
"Finished recover at ..."
Looks to have run OK.
But then, when I try to put the tablesopace back online...
"failure of sql command on default channel at...."
"failure during parse/execution of SQL statement: alter tablespace foo online"
"file 1 needs media recovery"
"data file 1: 'dbdisk/mydb/foo.dbf'"
What gives?
Thanks for any help

I've read the books and googled this to death.
Looks like I'm screwed.
At this point, I don't even care about the datafile or the tablespace it contained. I just want my database back.
I dropped the tablespace and it's datafile (and it's data too). I'll have to repopulate from scratch.
Lesson learned
This is what I want to do.....
I want to do a 1x/wk backup of a schema (not the whole DB, I don't have enough disk space for that, just 1 of the schemas). I've designed the thing such that each schema has it;s own tablespaces (no overlap) and each tablespace maps to a single datafile.
I would have liked to do some sort of online backup of the schema (read/write while backup is happening), but I'll settle for read only. If Oracle can't hack that, then I'll take the tablespaces offline.
The schema contains hundreds of millions of records, and the load preocess involves several times that number of data manipulation statements (deletes, updates, inserts). I'd rather not use archivelog mode because I don't have the disk space for it. And, given the volume and nature of the data I'm loading (hundreds of millions of records, created from the data in large raw data files), and how it's being loaded (precompiled C/SQL programs), I would never have need to "rerun" the enormous archives for any reason.
So...
1) backup a single schema (an exclusive set of tablespaces/datafiles)
2) as "online" as possible
3) in noarchivelog mode.
The only thing that I've seen that can do this is EXPORT/IMPORT. I tried that, but extrapolating IMPORT performance, even with all the streamlining recommendations, would take over 3 days. For this reason, IMPORT is not a viable option.
-dave

ORA-01195: online backup of file 65 needs more recovery to be consistent

Hi,
I was doing a clone by taking the hot backup from prod to dev. The backup was good. And then I created the control file, Then I passed the command
recover database until cancel using backup controlfile;
It asked for the archived logs files. I supplied them until current time.
Then I canceled.
That's when I got this error
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01195: online backup of file 65 needs more recovery to be consistent
ORA-01110: data file 65: '/d10/oradata/dwdev/kt01.dbf'
ORA-01112: media recovery not started
What am I doing wrong? I have not yet passed the command "Alter database open resetlogs"
Should I do more logswitches in prod and pass those files to dev ? Or should I just put the kt tablespace in backup mode and copy the data files?

Which set of archivelogs did you copy over to apply ? All the archivelogs from the first ALTER TABLESPACE ... BEGIN BACKUP to the archivelogs subsequent to the last ALTER TABLESPACE ... END BACKUP ?
In the cloned datadabase, what messages do you see in the alert.log on having issued the RECOVER DATABASE command ? Does it complain about the datafiles being fuzzy ? Which archivelogs does it show as having been applied ?
Can you check the log sequence numbers for the duration of the Backup PLUS ArchiveLogs subsequent to the Backup ?

Instance recovery mechanism

Hi,
I try to understand the mechanism of instance recovery of Oracle 8i/ Oracle 9i database and I am little bit confused, since I got some opposed information about that.
Please find below my questions:
1. Is SCN number assigned to all transactions or ONLY to committed transactions?
2. Is the checkpoint number the highest SCN number after an checkpoint event?
3. After checkpoint event, dirty buffer are written to database files by DBWR. Does DBWR write only dirty buffers of committet transactions or does DBWR write out all dirty buffers in the DB buffer cache?
Thanks in advance for your answers!
regards
Peter

1. The system change number (SCN) is updated whenever there is a commit.
2. If you are talking about the checkpoint_change# in the v$database table, yes
3. All dirty buffers are written to disk. Data files can and do contain uncommitted data
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

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....
Amanjit

Online 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.

Uncommited transactions remain after Instance Recovery

After Instance Recovery, the database seems to contain uncommitted transactions. Please provide an explanation for the following:
create table t1
as
select *
from all_objects;
commit;
create table t2
as
select *
from all_objects;
update t2
set object_id = 1 where rownum = 1;
shutdown abort;
Neither table t2 nor the update to it were committed (right?), therefore, once the database starts up t2 should not be there. On the contrary, it is still there. In the Oracle Database Backup and Recovery Advanced Guide 10g Release 2, page 11-9, explains how the uncommitted transactions are removed (rolled back) in the Roll Backward step (transaction recovery) of the Instance recovery process.
Any insight on this is highly appreciated. Thanks.

Note also following scenario run with SYSDBA privileges:
bas002> select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Prod
PL/SQL Release 10.2.0.2.0 - Production
CORE    10.2.0.2.0      Production
TNS for 32-bit Windows: Version 10.2.0.2.0 - Production
NLSRTL Version 10.2.0.2.0 - Production
bas002>
bas002> drop table t2;
drop table t2
ERROR at line 1:
ORA-00942: table or view does not exist
bas002> create table t2
2 as
3 select *
4 from all_objects;
Table created.
bas002>
bas002> update t2
2 set object_id = 1 where object_id=258;
1 row updated.
bas002>
bas002> shutdown abort;
ORACLE instance shut down.
bas002> startup
ORACLE instance started.
Total System Global Area 192937984 bytes
Fixed Size                  1288484 bytes
Variable Size             130025180 bytes
Database Buffers           54525952 bytes
Redo Buffers                7098368 bytes
Database mounted.
Database opened.
bas002>
bas002> select count(*) from t2 where object_id=1;
COUNT(*)
         0
bas002>Message was edited by:
Pierre Forstmann

ORA-01113: file5 needs media recovery

Dear All
When I connected to my database, I got message the database is shutdown.
When I shutdown my database and try to restart my database again, I got the following errors:
ORA-01113: file 5 needs media recovery
ORA-01110: data file 5: C:\DB11\ORADATA\DB11\Example01.dbf
Many thanks, Helen

Dear Helen,
Data from Example users like HR and any other example schemas if created in installation.
If you create any user and assgn other tablespace (like users) you will not lose that data's.
For more safely, shudown database and copy all you datafiles, controll file and redo log files other places (Cold Backup)
Regards,
Reza

Need Instance Recovery?

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