Re: Strange problem with controlfile
- From: Andy Klock <andy@xxxxxxxxxxxxxxx>
- To: Sreejith S Nair <sreejithsna@xxxxxxxxx>
- Date: Thu, 29 Dec 2011 12:09:55 -0500
On Thu, Dec 29, 2011 at 12:05 PM, Sreejith S Nair <sreejithsna@xxxxxxxxx>wrote:
> I have mounted the instance using pfile with one good copy o control file.
> Database is up and running for the users. However, I do not understand why
> oracle complains for control file when I gave startup no mount. As per my
> understanding control file is read only when database is mounted. This
> sounds very strange after all !
>
>
> Hi Sreejith,
The problem is you have set a control_file that does not have an alias that
was system generated.
The rules about nomount have changed a little in regards to ASM. Oracle
does check if the controlfiles have a system generated alias (sometimes)
when starting with NOMOUNT, as you experienced.
-- +DATA/ora11gr2/controlfile/current.andy doesn't exist
SQL> alter system set control_files =
'+DATA/ora11gr2/controlfile/current.264.765465815,
+DATA/ora11gr2/controlfile/current.andy' scope=spfile;
System altered.
SQL> shutdown immediate;
ORA-01507: database not mounted
ORACLE instance shut down.
SQL> startup nomount;
ORA-15124: ASM file name '+DATA/ora11gr2/controlfile/current.264.765465815,
+DATA/ora11gr2/controlfile/current.andy' contains an invalid alias name
Since +DATA/ora11gr2/controlfile/current.andy doesn't exist (and even if it
did, it would need to have been system generated anyway). You can get
around this check by referencing a non ASM controlfile at the beginning of
the parameter values (it doesn't need to exist either, but it disables the
alias check)
SQL> !grep control init.test
*.control_files='/oracle/andy.ctl,
+DATA/ora11gr2/controlfile/current.264.765465815,+DATA/ora11gr2/controlfile/current.andy'
SQL> startup nomount pfile=init.test
ORACLE instance started.
Total System Global Area 534462464 bytes
Fixed Size 2228200 bytes
Variable Size 339738648 bytes
Database Buffers 184549376 bytes
Redo Buffers 7946240 bytes
SQL> sho parameter control_files
NAME TYPE VALUE
------------------------------------ -----------
------------------------------
control_files string /oracle/andy.ctl,
+DATA/ora11g
r2/controlfile/current.264.765
465815,+DATA/ora11gr2/controlf
ile/current.andy
SQL> !ls /oracle/andy.ctl
ls: /oracle/andy.ctl: No such file or directory
Not really useful, but a useful hack in a pinch. As for the "aliases",
these can be queried with V$ASM_ALIAS. The control files need to be system
generated.
Now I did what you did and did a copy of a controlfile with asmcmd:
ASMCMD> cp current.275.765465817 current.275.765465817.test
copying +DATA/ORA11GR2/controlfile/current.275.765465817 ->
+DATA/ORA11GR2/controlfile/current.275.765465817.test
ASMCMD> rm current.275.765465817
ASMCMD> ls
current.264.765465815
current.275.765465817.test
This file is not "system generated" but Oracle will create a system
generated alias for me.
SQL> select name , system_created from v$asm_alias where name like
'current%';
NAME S
---------------------------------------------------------------------- -
current.275.765465817.test.272.771158129 Y
<-- notice the Y
current.264.765465815 Y
current.275.765465817.test N
You can see this also if you "ls -l" the file I cp'd:
ASMCMD> ls -l current.275.765465817.test
Type Redund Striped Time Sys Name
N
current.275.765465817.test =>
+DATA/ASM/CONTROLFILE/current.275.765465817.test.272.771158129
I can't use current.275.765465817.test as a control_file, but I can use the
alias current.275.765465817.test.272.771158129.
SQL> !grep control_files init.test
*.control_files='+DATA/asm/controlfile/current.275.765465817.test.272.771158129',
'+DATA/ora11gr2/controlfile/current.264.765465815'
SQL> startup nomount pfile=init.test
ORACLE instance started.
Total System Global Area 534462464 bytes
Fixed Size 2228200 bytes
Variable Size 339738648 bytes
Database Buffers 184549376 bytes
Redo Buffers 7946240 bytes
All the above is sort of convoluted and should be avoided following the doc
to restore a controlfile to the new diskgroup and let Oracle come up with
the name.
SQL> alter system set
control_files='+DATA1/fdstg2/controlfile/current.260.676234913','+DATA2'
scope=spfile sid='*';
RMAN> restore controlfile from
'+DATA1/fdstg2/controlfile/current.260.676234913';
RMAN will tell you where on +DATA2 it placed the restored controlfile. Then
set the control_files to this new path.
SQL> alter system set
control_files='+DATA1/fdstg2/controlfile/current.260.676234913','+DATA2/new_path...'
scope=spfile sid='*';
Hope this helps clear up controlfiles on ASM.
--
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