Database Backup And Recover

Front 1

Failures can generally be divided into the following categories:

Back 1

Statement failure
User process failure
Network failure
User error
Instance failure
Media failure

Front 2

Statement Failure
Typical Problem
Attempts to enter invalid data into a table

Back 2

Possible Solution
Work with users to validate and correct data.

Front 3

Statement Failure
Typical Problem
Attempts to perform operations with insufficient privileges

Back 3

Possible Solution
Provide appropriate object or system privileges.

Front 4

Statement Failure
Typical Problem
Attempts to allocate space that fail

Back 4

Possible Solution
Provide appropriate object or system privileges.

Front 5

Statement Failure
Typical Problem
Attempts to allocate space that fail

Back 5

Possible Solution
Enable resumable space
allocation.
Increase owner quota.
Add space to tablespace.

Front 6

Statement Failure
Typical Problem
Logic errors in applications

Back 6

Possible Solution
Work with developers to correct program errors.

Front 7

User Process Failure
Typical Problems
A user performs an abnormal disconnect.
A user’s session is abnormally terminated.
A user experiences a program error that terminates the session.

Back 7

A DBA’s action is not usually needed to resolve user process failures. Instance background processes roll back uncommitted changes and release locks.


Watch for trends.

Front 8

Network Failure
Typical Problems
Listener fails.

Back 8

Possible Solutions
Configure a backup listener and connect-time failover.

Front 9

Network Failure
Typical Problems
Network Interface Card (NIC) fails

Back 9

Possible Solutions
Configure multiple network cards.

Front 10

Network Failure
Typical Problems
Network connection fails.

Back 10

Possible Solutions
Configure a backup network connection.

Front 11

User Error
Typical Causes
User inadvertently deletes or modifies data.

Back 11

Possible Solutions
Roll back transaction and dependent transactions or rewind table.

Front 12

User Error
Typical Causes
User drops a table.

Back 12

Possible Solutions
Recover table from recycle bin.

Front 13

What do you use??
Viewing past states of data
Winding data back and forth in time
Assisting users in error analysis and recover

Back 13

Flashback technology:

Front 14

used For error analysis:

Back 14

Oracle Flashback Query
Oracle Flashback Versions Query
Oracle Flashback Transaction Query

Front 15

For error recovery:

Back 15

Oracle Flashback Transaction Backout
Oracle Flashback Table
Oracle Flashback Drop
Oracle Flashback Database

Front 16

Instance Failure
Typical Cause
Power outage
Hardware failure
Failure of one of the critical background processes
Emergency shutdown procedures

Back 16

Possible solutions
Restart the instance by using the STARTUP command. Recovering from instance failure is automatic, including rolling forward changes in the redo logs and then rolling back any uncommitted transactions.

Investigate the causes of failure by using the alert log, trace files, and Enterprise Manager.

Front 17

What is Responsible for
Updating data file headers with
checkpoint information
Updating control files with
checkpoint information
Signaling DBWn at
full checkpoints

Back 17

CKPT is responsible for that
Checkpoint process

Front 18

Redo Log Files and Log Writer

Back 18

Front 19

Understanding Instance Recovery
Involves two distinct operations:

Back 19

Rolling forward: Redo log changes (both committed and uncommited) are applied to data files.

Rolling back: Changes that are made but not committed are returned to their original state.

Front 20

Statement failure is never by design and always requires the DBA to address the issue.
True
False

Back 20

False

Front 21

Phases of Instance Recovery

Back 21

1. Startup instance (data filesare out of sync)
2. Roll forward (redo)
3. Committed and uncommitted data in files
4. Database opened
5. Roll back (undo)
6. Committed data in files

Front 22

Tuning Instance Recovery

Back 22

During instance recovery, the transactions between the checkpoint position and the end of redo log must be applied to data files.
You tune instance recovery by controlling the difference between the checkpoint position and the end of redo log.

Front 23

The FAST_START_MTTR_TARGET

Back 23

initialization parameter simplifies the configuration

Front 24

Using the MTTR Advisor

Back 24

Specify the desired time in seconds or minutes.
The default value is 0 (disabled).
The maximum value is 3,600 seconds (one hour).

Front 25

Oracle Corporation defines media failure as any failure that results in the loss or corruption of one or more database files whats there name?

Back 25

(data, control, or redo log file).

Front 26

Configuring for Recoverability
To provide the best protection for your data, you must:

Back 26

Schedule regular backups Most media failures require that you restore the lost or damaged file from backup.

Multiplex control filesAll control files associated with a database are identical. Recovering from the loss of a single control file is not difficult; recovering from the loss of all control files is much more challenging. Guard against losing all control files by having at least two copies.

Multiplex redo log groups

Front 27

Configuring the Fast Recovery Area
The fast recovery area is a space that is set aside on the disk to contain archived logs, backups, flashback logs, multiplexed control files, and multiplexed redo logs. A fast recovery area simplifies backup storage management and is strongly recommended.

Back 27

Just read the other side

Front 28

Which parameters configure the fast recovery area

Back 28

Location specified by the DB_RECOVERY_FILE_DEST parameter
Size specified by the DB_RECOVERY_FILE_DEST_SIZE

Front 29

Extra Bit

Back 29

startup command is used for instance recovery

Redo log files record changes to the database, should be multiplexed
to protect against loss

writes
when one third full
at commit
every 3 seconds
before dbwn
before clean shutdowns


Rolling forward-- both commited and uncommited
are applied to data files


Rolling Back--changes made but not commited
are returned to the origibal state

Front 30

startup command is used for what?

Back 30

instance recovery

Front 31

Redo log files record changes to the database, should be multiplexed , for what reason?

Back 31

To protect against loss

Front 32

Log writer writes at

Back 32

writes
when one third full
at commit
every 3 seconds
before dbwn
before clean shutdowns

Front 33

Rolling forward-- both commited and uncommited
are applied to data files


Rolling Back--changes made but not commited
are returned to the origibal state

Back 33

Rolling forward-- both commited and uncommited
are applied to data files


Rolling Back--changes made but not commited
are returned to the origibal state