Question: I am getting an I/O error at database startup time:
SQL> startup
ORACLE instance started.
ORA-00221: error on write to
control file
ORA-00206: error in writing (block 1, # blocks 1) of control
file
ORA-00202: control file: '/U02/database/mydb/control01.ctl'
ORA-27072: File I/O error
Linux Error: 11: Resource temporarily
unavailable
**********************************
Thread 1 advanced to log sequence
7268
Errors in file
/oracle/product/10.2.0/db_1/admin/alpaorcl/bdump/alpaorcl_arc1_25850.trc:
ORA-00202: control file: '/home/logdisk2/oradata/alpaorcl/control03.ctl'
ORA-27091: unable to queue I/O
ORA-27072: File I/O error
Linux-x86_64 Error: 5: Input/output error
Is
this just a I/O error con the controlfile, or do I have a real disk failure?
Answer: Your first step is to ensure that you have a "real" disk I/O
error, and not a phantom I/O error, and the OS logs will provide this
information.
I would start by seeing if the controlfile is really
corrupt. I would start by seeing if you can issue the UNIX "view" or
"strings" command on the controlfile, and check your OS syslog for file I/O
errors.
Basically you need to have your SYSADMIN staff call
you DASD vendor to come and replace your damaged media.
Next, I would take one of the other copies of your control
file and replace the one referenced in your startup. If you have not
multiplexed your controlfiles, you will have made a daily backup of your
controlfile that you can grab from the trace file.
alter database backup
controlfile to trace;
Normally, all I/O errors are quite serious, and you
need to open an SR with Oracle technical support.
The remedy for a
disk I/O error at startup is to open an SR, restore the disk to a working
device, and restore the database using RMAN. Oracle tech support may
advise you to employ
hidden recovery parameters.