I am new to DBA.
I am maintainting an Oracle 8i server.
Can someone please explain step-by-step procedure with COMMANDS of how to take Hot backups of Redo Log files.
Thanks in advance.
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I am new to DBA.
I am maintainting an Oracle 8i server.
Can someone please explain step-by-step procedure with COMMANDS of how to take Hot backups of Redo Log files.
Thanks in advance.
You don't really gain anything getting a backup of an online redo log - they are open and not in a consistent state to be useful in a recovery.
You should create multiple copies of redo log files on
different physical device by command
ALTER DATABASE ADD LOGFILE MEMBER ....
Thanks. Could you pls explain some details of how to do this.Quote:
Originally posted by uncleserg
You don't really gain anything getting a backup of an online redo log - they are open and not in a consistent state to be useful in a recovery.
You should create multiple copies of redo log files on
different physical device by command
ALTER DATABASE ADD LOGFILE MEMBER ....
1. Connect to database as sysdba
sqlplus /nolog
connect sys/passwd as sysdba;
2. Look at your redo log configuration
SQL> select * from v$logfile;
GROUP# STATUS TYPE
---------- ------- -------
MEMBER
------------------------------------------------------
1 ONLINE
/u01/oracle/ora9i/oradata/ln9i/redo01.log
2 STALE ONLINE
/u01/oracle/ora9i/oradata/ln9i/redo02.log
3 STALE ONLINE
/u01/oracle/ora9i/oradata/ln9i/redo03.log
There are 3 redo groups, each has one member.
2. Add addition member to each group
alter database add logfile member '/u00/oracle/ora9i/oradata/ln9i/redo01.log'
to group 1;
alter database add logfile member '/u00/oracle/ora9i/oradata/ln9i/redo02.log'
to group 2;
alter database add logfile member '/u00/oracle/ora9i/oradata/ln9i/redo03.log'
to group 3;
3.
SQL> select * from v$logfile;
GROUP# STATUS TYPE
---------- ------- -------
MEMBER
----------------------------------------------
1 ONLINE
/u01/oracle/ora9i/oradata/ln9i/redo01.log
2 STALE ONLINE
/u01/oracle/ora9i/oradata/ln9i/redo02.log
3 STALE ONLINE
/u01/oracle/ora9i/oradata/ln9i/redo03.log
1 INVALID ONLINE
/u00/oracle/ora9i/oradata/ln9i/redo01.log
2 INVALID ONLINE
/u00/oracle/ora9i/oradata/ln9i/redo02.log
3 INVALID ONLINE
/u00/oracle/ora9i/oradata/ln9i/redo03.log
Now each group has 2 members located on different disk.
If disk with /u01 filesystem fails I can use copy of my redo
logs on /u00.
You should never back up your redo logs ever!
...except, of course, in a cold backup.
As far as I remember, even then Jurij neglects them opening with resetlogs, right Jurij?Quote:
Originally posted by marist89
...except, of course, in a cold backup.
If you've done a proper cold backup (shutdown normal, transactional or immediate), then the database is shut down in a consistent state anyway, and the logs are not necessary for instance recovery. No resetlogs will be necessary to open a cold backup database. As long as you also backed up your control file . . .
if your database is in ARCHIVELOG mode then you have the backups.
True. And its not just me - you'll never find RMAN to back up redo logs, not even with cold backups...Quote:
Originally posted by julian
As far as I remember, even then Jurij neglects them opening with resetlogs, right Jurij?Quote:
Originally posted by marist89
...except, of course, in a cold backup.