Home » RDBMS Server » Backup & Recovery » Backup and recovery
icon14.gif  Backup and recovery [message #137138] Tue, 13 September 2005 07:20 Go to next message
oradba16
Messages: 54
Registered: September 2005
Member
if we lost datafiles when the database is open, meanwhile the lost datafile belongs to system or undo segments. now how can we recover the lost datafiles without closing the database?
plz ans this with complete steps

with regards;
Boobathi.P
Re: Backup and recovery [message #137141 is a reply to message #137138] Tue, 13 September 2005 07:27 Go to previous messageGo to next message
alliejane
Messages: 59
Registered: July 2005
Location: Glasgow
Member
I'm afraid you can't, the only way to fix either the system datafiles or any datafile with an active segment is to do it at mounted stage..

As you can understand the system datafiles hold the datadictionary which is fundamental to operation.

In actual fact you will probably find that the database will crash down anyway and you will have no option but to fix while mounted.

Hope that helps.

Allie
Re: Backup and recovery [message #137142 is a reply to message #137138] Tue, 13 September 2005 07:28 Go to previous messageGo to next message
tarundua
Messages: 1080
Registered: June 2005
Location: India
Senior Member


1. System -- Strange the datafile belongs to System tablespace & ur database is still running. Recovery not possible without shutdown.


2. Undo -- If it belongs to undo tablespace then

--- Create a new undo tablespace.

--- Assign new undo tablespace as undo tablespace for database.

If there is any other issue explain ur problem properly with OS details & Oracle version. How u lost datafile ?

try to run this query while logged as sys :

SQL> select open_mode from v$database;

and post the output.

regards,
tarun
Re: Backup and recovery [message #137153 is a reply to message #137142] Tue, 13 September 2005 07:58 Go to previous messageGo to next message
alliejane
Messages: 59
Registered: July 2005
Location: Glasgow
Member
Just as an aside point...

Assigning a new undo tablespace would be a temporary solution, however if you have any transactions running that still require to record UNDO(updates not finished) or a transaction needs to rollback, your back to the same problem.

In my experience, when the UNDO datafiles are lost, the next time oracle tries to write UNDO, it will also crash the database.

A Smile

Re: Backup and recovery [message #137157 is a reply to message #137138] Tue, 13 September 2005 08:24 Go to previous messageGo to next message
oradba16
Messages: 54
Registered: September 2005
Member
hi,
actually when i go through the book there in complete recovery methods, it is given that 'closed database recovery' is used when:

1.recovered files belong to the system or undo segment tablespace.
2.whole database or a majority of the datafiles, need recovery.

for the other methods such as
1.open database recovery with database initially opened.
2." " " " " closed.
3.datafile recovery without datafile backup

it is given that recovered file do not belongs to system or undo segments.
so doubt arises in me how can we recover datafile in open stage without closing, if datafile belongs to this system and undo segments tablespaces.

so i ask u people can we do recover in open stage? is it possible? if yes how can we recover? if no, give reason? and what we hav to do at this stage?

[Updated on: Tue, 13 September 2005 08:44]

Report message to a moderator

Re: Backup and recovery [message #137266 is a reply to message #137157] Wed, 14 September 2005 03:31 Go to previous message
alliejane
Messages: 59
Registered: July 2005
Location: Glasgow
Member
I'm not sure if I'm understanding your question..

The question you originally asked is "if we lost datafiles when the database is open, meanwhile the lost datafile belongs to system or undo segments. now how can we recover the lost datafiles without closing the database?"

The plain answer to that is NO...

Not sure why you keep asking the same question over again when the answer has been given.

If I'm misunderstanding your question then apologies, however if you are still confused then please reword your question, stating your concerns and the issue that you are experiencing.

Alison
Previous Topic: BACK UP AND RECOVERY
Next Topic: how to recover datafiles belong to system tbs in open stage
Goto Forum:
  


Current Time: Fri Apr 19 18:19:09 CDT 2024