Oralce OMF features (ii) OMF management of Oracle log files

Second, the OMF management of the log file

Log file management parameters: Db_create_online_log_dest_n

Db_create_online_log_dest_n:oracle the default path when you create an online log file and a control file without explicitly specifying a path

--View the parameters of the log file, the following is an db_create_online parameter that is not set

Sql> Show PARAMETER Db_create_online

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Db_create_online_log_dest_1 string

Db_create_online_log_dest_2 string

Db_create_online_log_dest_3 string

Db_create_online_log_dest_4 string

Db_create_online_log_dest_5 string

--From the above you can see that the system reserved a log group members to form OMF, in general, we just need a member. Because you set a parameter file here

--The following is the creation of a log file without a setting, the default is to place a file in the path of the data file and in the flashback area, because both of these paths are OMF paths, as follows:

Sql> SELECT member from V$logfile;

Member

--------------------------------------------------------------------------------

/u01/app/oracle/oradata/orcl/redo03.log

/u01/app/oracle/oradata/orcl/redo02.log

/u01/app/oracle/oradata/orcl/redo01.log

/u01/app/oracle/oradata/orcl/orcl/onlinelog/o1_mf_4_5vtgzjyz_.log

/u01/app/oracle/flash_recovery_area/orcl/onlinelog/o1_mf_4_5vtgzlhb_.log

Sql> Show PARAMETER Db_create_file_dest

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Db_create_file_dest STRING/U01/APP/ORACLE/ORADATA/ORCL

Sql> Show Parameter Db_recovery_file_dest

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Db_recovery_file_dest String/u01/app/oracle/flash_recovery

_area

Db_recovery_file_dest_size Big Integer 2G

--Store the log file under the specified Disk1,disk2

Sql> Ho Mkdir/u01/app/oracle/disk1

Sql> Ho Mkdir/u01/app/oracle/disk2

sql> ALTER SYSTEM SET db_create_online_log_dest_1 = '/u01/app/oracle/disk1 ';

System altered.

sql> ALTER SYSTEM SET db_create_online_log_dest_2 = '/u01/app/oracle/disk2 ';

System altered.

sql> ALTER DATABASE ADD logfile;

Database altered.

Sql> SELECT * from V$logfile; /* You can see the new log file under Disk1,disk2 * * *

group# STATUS TYPE member Is_

---------- ------- ------- ---------------------------------------- ---

3 Online/u01/app/oracle/oradata/orcl/redo03.log NO

2 Online/u01/app/oracle/oradata/orcl/redo02.log NO

1 Online/u01/app/oracle/oradata/orcl/redo01.log NO

4 Online/u01/app/oracle/oradata/orcl/orcl/online NO

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