In this practice you will make multiple control
files to prevent a single point of failure of the database.
Assumptions
·
The directory path to the control files in your
database will differ from the example in the practice.
Instructions
1. Set
up mirroring of control files so you have at least two control files. Place
your second control file on a disk drive different from the first control file.
For practice purposes you could place it in another directory. On UNIX systems,
it is also very important that the Oracle user have read/write permissions on
the new copy of the control file. If the Oracle user does not have the correct
permissions you will typically receive the “end of file on
communications channel” error.
|
·
Shut down the database:
SQL> SHUTDOWN IMMEDIATE; ·
Copy the existing control file to a
different device using operating system commands: (Your directory path and
file names will differ.)
$cp -p
$HOME/ORADATA/u01/ctrl01.ctl
·
Make sure that the Oracle user can read
and write to these new files.
$chmod g+wx
$HOME/ORADATA/u02/ctrl02.ctl ·
Edit or add the CONTROL_FILES parameter and specify names for all the
controlfiles:
·
Start up the instance and open the
database:
SQL> STARTUP
PFILE=$HOME/…/init<sid>.ora ·
Show the value of the control_files
parameter:
SQL> show parameter control_files
|
This completes this
practice.
ã Oracle Corporation, 2002
In this
practice you will make multiple redo log files for each redo group to prevent a
single point of failure of the database.
Assumptions
·
The directory
path to the redo log files in your database will differ from the example in the
practice.
Instructions
1.
Set up
mirroring of redo log files so you have at least two members per log group.
Place your second redo log file of the group on a different disk drive than the
first file. For practice purposes you could place it in another directory.
· SQL> alter database add logfile member '$HOME/ORADATA/u04/log01b.rdo' to group 1, '$HOME/ORADATA/u04/log02b.rdo' to group 2; Database altered.·
SQL> select member from v$logfile; MEMBER -------------------------------------- /databases/ed21/ORADATA/u03/log01a.rdo
|
This completes this practice.
ã Oracle Corporation, 2002
In this
practice you will manipulate the parameters that are used to reduce mean time
to recover.
Instructions
1.
Show the current
settings for the parameters that control mean time to recover.
|
SQL> show parameter recovery NAME TYPE VALUE ------------------------------------
----------- ----- recovery_parallelism integer 0 SQL> show parameter fast_start NAME TYPE VALUE ------------------------------------
----------- ----- fast_start_io_target integer 0 fast_start_mttr_target integer 300 fast_start_parallel_rollback string LOW SQL> show parameter log_check NAME TYPE VALUE ------------------------------------
----------- ----- log_checkpoint_interval integer 0 log_checkpoint_timeout integer 1800 log_checkpoints_to_alert boolean FALSE |
2.
Dynamically
alter the mean time to recover target parameter to 10 minutes recovery time.
|
SQL>
alter system set fast_start_mttr_target=600; System
altered. SQL>
show parameter fast_start_mttr_target NAME TYPE VALUE -----------------------
-------- ---------- fast_start_mttr_target integer 600 SQL> |
This completes this practice.
ã Oracle Corporation, 2002
