How many redo log groups should I have?
two redo log groups
Every database must have at least two redo log groups. Redo log files contain all the information necessary to recover lost data in your database.
How do you add more redo log groups?
To create a new group of redo log files, use the SQL statement ALTER DATABASE with the ADD LOGFILE clause. The following statement adds a new group of redo logs to the database: ALTER DATABASE ADD LOGFILE (‘/oracle/dbs/log1c.
How do you do multiplex redo logs?
To multiplex your redo log, you must add members to each redo log group. It is not required that redo log groups be symmetrical, but Oracle recommends that your groups all have the same number of members. A database must have a minimum of two redo log groups.
What are the archived redo logs used for?
Archived redo logs are used to recover a database or update a standby database. Before you restore, you must locate the file. When you locate the files, ensure that the database is in the Open state.
How do I recover lost redo log files?
Recovering After the Loss of All Members of an Online Redo Log Group
- Locate the filename of the lost redo log in V$LOGFILE and then look for the group number corresponding to it.
- Determine which groups are active.
- If the affected group is inactive, follow the procedure in Losing an Inactive Online Redo Log Group.
What is written in redo log files?
Redo log files are filled with redo records. A redo record, also called a redo entry, is made up of a group of change vectors, each of which is a description of a change made to a single block in the database. Redo records can also be written to a redo log file before the corresponding transaction is committed.
How do I view a redo log file?
The V$LOGFILE view can be used to find the datafiles for the redo logs. SVRMGR> select * from V$LOGFILE; GROUP# STATUS MEMBER —— —— —————————— 1 /t01/oradata/MYDB/redo.