RECOVERY MANAGER

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RECOVERY MANAGER

• Presenter
• STEPHEN SIEW

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WHAT IS RMAN ?

• RMAN is a stand-alone application that makes
• a client connection to the Oracle DB to access
• internal backup and recovery packages. It is, at
• its core, nothing more than a command
• Interpreter that takes simplified commands you
• type and turns those commands into remote
• calls (RPCs) that are executed at the DB.

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NEW FEATURES OF RMANPART I

• Automation of backup, restore and recovery
  operations
• Block media recovery
• Whole database backups or backups of any
  logical unit control file, datafile, tablespace
  or archive log
• Offline and Online backups
• Integrated with 3rd Party Media Management
  Vendors to backup to tape
• Two types of backup image copies to disk or
  Recovery Manager backup sets
• Intelligent management of the archived redo
  logs for both backup and recovery
• Proxy Copy Backup Accelerator for fast copy
  technology at the storage subsystem level
• Integration with Oracle Enterprise Managers
  Backup Manager GUI

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NEW FEATURES OF RMANPART II

• Incremental backups at the Oracle block level
  for high performance backup and recovery
• Omission of empty blocks during backup for
  optimization
• Recoverability redundancy when both
  incrementals and archiving are used
• No extra redo is generated during online
  database backup
• Intelligent buffering with multiplexing of
  multiple input files for high speed tape
  streaming
• Support for Oracle Real Application Clusters
  backup and recovery
• Ability to recover through unrecoverable
  operations, when using incremental backups
• O/S-independent scripting language

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What does RMAN do?

• It does very little. The backing up and the
• recovery of the DB is done by the processes.
• The Oracle DB has internal packages that
• Actually take the pl/sql blocks passed from
• RMAN and turn them into system calls to
• read from, write to, the disk subsystem of
• your DB server.

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Who carry the weight?

• The RMAN is make up of two pieces
• The executable file
• The recover.bsq file
• The recover.bsq file is the brains of the whole
• operation. It is essentially the library file
  from which the
• executable file extracts code for creating pl/sql
  calls to
• the target. These two files are invariably
  linked, and
• logically make up the RMAN client utility. These
  two
• must be the same version to work.

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How does the RMAN utility works ?

• RMAN utility interprets commands you provide
• into pl/sql calls that are remotely executed at
  the
• target. These commands are interpreted by the
• executable translator, and then matched to pl/sql
• blocks in the recover.bsq file. RMAN then passes
• These RPCs to the DB to gather info based on
• what you have requested.

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RMAN ProcessStarting the Backup

• RMAN makes the bequeath connection to the
• target DB . It checks the the variable
• ORACLE_SID for an instance name, spawns
• a server process at that instance, logging in as
  a
• SYSDBA user. This connects as the internal DB
• user SYS. RMAN immediately spawns the
• channel processes that will perform the backup.

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RMAN Compilation Call to sys.dbms_rcvman

• It request DB schematic info from the target DB
• controlfile, starting with the determinations of
• Target DB version version info from the
• controlfile What type of controlfile? What
• is the current sequence number? When was
• it created? Requesting info for each datafile
  in the
• DB and whether it is offline. It gathers which
  disk each
• file is on and how to dole out work.

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RMAN Creating the Backupsetdbms_backup_restore

• After the list is compiled, it begin the backup
• process itself. To guarantee consistency, it then
  
• builds the snapshot controlfile. If one already
• exists, it overwrites it with a new one. Then
• RMAN creates the call to the package to create
• the backup piece. The backup piece will be built
• in the default file location unless specified
  otherwise.
• Unix ORACLE_HOME/dbs Win in database dir.

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RMAN Allocating the memory

• After it is allocated, it initiates the backup
  piece.
• The backup piece will be given a default name
• that guarantees uniqueness. It determines if
  there
• will be enough space for the backup. In 8i it
  preallocates
• space for backups but not in 9i. Once the backup
  piece is
• initiated, then the channel process can begin the
  DB
• backup process. It determines if you are using
  spfile, it
• then backs it up and if has automatic controlfile
  backup
• is set, it will backup the controlfile.

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RMAN The Backup

• It backed up the spfile and controlfile, and it
  is
• time to begin the datafile reads to pull data
  blocks
• into memory. The channel process does this by
• doing a read-ahead on the disk and pulling
• several blocks into memory at the same time.
• Then, memory-to-memory write from input
• buffer to output buffer occurs. During this write,

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RMAN Writing in Memory

• RMAN determines if the block has ever initialized
  or if the
• block header information is zeroed out. If it is
  an unused
• block, the write to the output buffer never
  occurs. If the
• block has been used, RMAN performs a checksum on
  the
• block. If the header and footer of the block do
  not match,
• RMAN indicates a corrupt block and aborts the
  backup. If
• It matches, the block is written to the output
  buffer. Once
• the output buffer is filled to capacity, it dump
  the buffers to the
• backup file location. There is no order to the
  blocks in the dump file.

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RMAN START UP DB

• To start the database using RMAN, at the RMAN
• prompt (assuming you are already in RMAN),
• RMANgt startup
• RMAN-06196 Oracle instance started
• RMAN-06199 database mounted
• RMAN-06400 database opened
• Total System Global Area 94525468
  bytes
• Fixed Size 75804
  bytes
• Variable Size 27262976
  bytes
• Database Buffers 67108864
  bytes
• Redo Buffers 77824
  bytes

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RMAN Different Startup Mode

• To start the database in nomount mode.
• RMANgt startup nomount
• To start the database in mount mode.
• RMANgt startup moun

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RMAN SHUTDOWN THE DB

• To shut down the database using RMAN
• RMANgt shutdown
• RMAN-06405 database closed
• RMAN-06404 database dismounted
• RMAN-06402 Oracle instance shut down
• To exit RMAN, just type in 'exit" at the prompt.
• RMANgt exit

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RMAN Shutdown Mode

• To shutdown immediate.
• RMANgt shutdown immediate
• To shutdown abort.
• RMANgt shutdown abort

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Oracle9i RMAN Improvements

• Streamlined syntax
• Configurable persistent channel settings
• Automatic backup of control files
• Backup optimization
• Restore optimization
• Block-level recovery
• Enhancement to archived redo log backups

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RMAN - CONFIGURATIONS

• The channel configuration settings are stored
• in the target database control file, so you don't
• have to re-issue channel configuration
• commands each time you perform a backup,
• restore, or copy operation. This reduces the
• amount of code required to perform an RMAN
• command, which in turn lessens the possibility
• of human error.

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RMAN SHOW ALL PART I

• RMANgt show all 
• using target database controlfile instead of
  recovery catalog
• RMAN configuration parameters are
• CONFIGURE RETENTION POLICY TO REDUNDANCY 1
  default
• CONFIGURE BACKUP OPTIMIZATION OFF
• CONFIGURE DEFAULT DEVICE TYPE TO DISK default
• CONFIGURE CONTROLFILE AUTOBACKUP OFF
• CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR
  DEVICE TYPE DISK TO F'

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RMAN SHOW ALLPART II

• CONFIGURE DEVICE TYPE DISK PARALLELISM 1
• CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE
  DISK
• TO 1 default
• CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE
  TYPE
• DISK TO 1 default
• CONFIGURE CHANNEL DEVICE TYPE DISK RATE 5 M
  FORMAT
• 'D\ORACLE\DEMO\ADMIN\RMAN_BKUP\dDBFs.BKUP'
• CONFIGURE MAXSETSIZE TO UNLIMITED default
• CONFIGURE SNAPSHOT CONTROLFILE NAME TO
• 'D\ORACLE\ORA92\DATABASE\SNCFDEMO.ORA' default

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RETENTION POLICYPART I

• There are two types of retention policies
  available in
• RMAN
• Recovery Window
• Redundancy
• RMANgt configure retention policy to redundancy 2
• RMANgt configure retention policy to recovery
• window of 7 days

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RETENTION POLICY PART II

• NOTE
• Media manager retention policies can cause havoc
  if they
• are not properly synchronized with RMAN
  retention policies! For instance, when using
  optimization ,y ou could have your media manager
  software remove a backup, and RMAN would not know
  about it. This might cause the DB to be
  unrecoverable.
• - If the control_file_record_keep_time DB
  parameter value is less than the time set for the
  retention policy, you will need to use a recovery
  catalog.

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DELETE OBSOLETE

• RMANgt report obsolete redundancy2
• RMANgt delete obsolete redundancy 2
• RMANgt delete obsolete recovery window of 7 days
• To remove orphaned backups that were
• created from a different incarnation of the DB.
• RMANgt delete obsolete orphan

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BACKUP FILE OPTIMIZATION

• With BFO, if RMAN is about to backup a file,
• and the file has already been backed up by the
• same device type, RMAN will skip the
• backup of that file. This includes both data
• files and archived redo logs backed up by
• RMAN. Oracle will determines whether the
• file has changed by comparing the datafile to the
  
• header of the backed up datafile.

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AUTO BACKUP OF CONTROL FILE

• It provides the capability to configure
• automated control file backups. When
• enabled, these automated control file backups
• Will occur any time a backup or copy
• command is issued either from the RMAN
• Command or within a run command block. Within
• the run block, the controlfile backup will occur
  only
• after the last backup command in the block has
• completed. You can also use the OS copy command.
  

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HOW TO RECOVER A CONTROLFILE?

• When you turn the controlfile autobackup
• on, it gives you the ability to recover the
• controlfile backup that was made as the
• result of an auto backup. You can use the
• restore controlfile from autobackup
• command. This allows you to restore the
• controlfile without repository.

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SNAPSHOT CONTROLFILE PART I

• The controlfile is a busy little file. It is
  responsible for schematic
• information about the DB, which includes
  checkpoint SCN info
• for recovery. The constant SCN and file
  management is critical
• to the livelihood of your DB, so the controlfile
  must be available
• for usage by the RDBMS on a constant basis.
• This poses a problem for RMAN. RMAN needs to get
  a
• consistent view of the controlfile when it sets
  out to make a
• backup of every datafile. It only needs to know
  the most recent
• checkpoint information and file schematic info at
  the time the
• backup begins.

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SNAPSHOT CONTROLFILE PART II

• After the backup starts, it needs this info to
  stay consistent for
• the duration of the backup operation in other
  words, it needs a
• read consistent view of the controlfile. With the
  constant updates
• from the DB, this is impossible unless RMAN
  were to lock the
• control file for the duration of the backup.
  That would mean the
• DB could not advance the checkpoint or switch
  logs or produce
• new archive logs. Impossible!
• To get around this, RMAN uses the snapshot
  controlfile, an exact

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SNAPSHOT CONTROLFILE PART III

• Copy of your controlfile that is only used by
  RMAN during
• backup and resync operations. At the beginning of
  these
• operations, RMAN refreshes the snapshot
  controlfile from the
• actual controlfile, thus putting a momentary lock
  on the
• controlfile. Then, RMAN switches to the snapshot
  and uses it for
• the duration of the backup in this way, it has
  read consistency
• without holding up DB activity.
• By default, it exists in the ORACLE_HOME/dbs
  UNIX and
• database on W2K.

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COLD DB BACKUP

• Cgt rman target /
• RMANgt shutdown immediate
• RMANgt startup mount
• RMANgt backup database
• RMANgt alter database open

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RECOVER FROM COLD DB BACKUP

• C\gt rman target /
• RMANgt startup
• Example It complain about it is missing a
  datafile(s).
• RMANgt shutdown immediate
• RMANgt startup nomount
• RMANgt set DBID ltenter the DBID of the DB heregt
• RMANgt restore controlfile from autobackup
• RMANgt alter database mount
• RMANgt restore database
• RMANgt recover database
• RMANgt alter database open

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ONLINE DATABASE BACKUP RECOVERY

• C\gt rman target /
• RMANgt backup database plus archivelog
• RMANgt restore database
• RMANgt recover database
• RMANgt alter database open

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BACKUP TABLESPACE DATAFILE PART I

• C\gt rman target /
• RMANgt backup tablespace users plus archivelog
• If the tablespace was dropped accidentally.  
• RMANgt startup mount
• RMANgt sql "alter tablespace users offline"
• RMANgt restore tablespace users
• RMANgt recover tablespace users
• RMANgt sql "alter tablespace users online"
• RMANgt alter database open

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BACKUP TABLESPACE DATAFILE PART II

• C\gt rman target /
• RMANgt sql "alter database datafile 3 offline'
• or
• RMANgt sql "alter database datafile
  d\oracle\oradata\rman_bkup\users01.dbf
  offline"
• RMANgt restore datafile 3
• or
• RMANgt restore datafile d\oracle\oradata\rman_bku
  p\users01.dbf
• RMANgt recover datafile 3
• or
• RMANgtrecover datafile d\oracle\oradata\rman_bkup
  \users01.dbf
• RMANgt sql "alter database datafile 3 online"
• or
• RMANgt sql " alter database datafile
• d\oracle\oradata\rman_bkup\users01.
  dbf onfline'

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RECOVER MISSING ARCHIVED LOG THAT WERE MISSING
PART I

• You accidentally deleted the archived logs that
  were restored by a DBA
• for disaster recovery. You go to the archive
  directory and see which
• archived logs (3,5,6 and 9)are missing.
• RMANgt startup mount
• RMANgt restore archivelog from logseq 2
• Starting restore at 16-APRIL-04
• using channel ORA_DISK_1
• archive log thread 1 sequence 2 is already on
  disk as file
• D\ORACLE\DEMO\ARCH\SSTT_2.ARCH

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RECOVER MISSING ARCHIVED LOG THAT WERE MISSING _
PART II

• Starting restore at 16-APRIL-04
• using channel ORA_DISK_1
• archive log thread 1 sequence 2 is already on
  disk as file
• D\ORACLE\DEMO\ARCH\SSTT_2.ARCH
• archive log thread 1 sequence 4 is already on
  disk as file
• D\ORACLE\SST\ARCH\SSTT_4.ARCH
• Piece handleD\ORACLE\DEMO\ADMIN\RMAN_BKUP\SSTDBF
  28.BKUP
• tagnull paramsNULL
• channel ORA_DISK_1 restore complete
• Finished restore at 16-DEC-02
• RMANgt

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BLOCK MEDIA RECOVERY
Assuming you got the following error
message ORA-01578 ORACLE data block corrupted
(file 19, block 44) ORA-01110 data file 19
d\oracle\DEMO\oradata\users01.dbf BMR applies
only to complete recovery because incomplete
recovery would leave the database in an
inconsistent state. RMANgt blockrecover datafile
19 block 44 RMANgt blockrecover datafile 19 block
44,66,127 RMANgt blockrecover datafile 19 block
44 datafile 22 block 203