Connecting to RMAN

Step 1: Set the following environment variables

ORACLE_SID
ORACLE_HOME
NLS_DATE_FORMAT

Step 2: Access to privileged OS account or user with Sysdba privilege. Only users with Sysdba privilege can connect to RMAN. Hence no need to specify as sysdba while connecting to RMAN.

$ cd $ORACLE_HOME/bin
$ rman target /

Recovery Manager: Release 10.2.0.1.0 - Production on Wed Jan 20 03:19:22 2010
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: IRIS (DBID=1460454352)

If you are using password file, then specify the username and password

$ rman target sys/syspassword

If you are accessing the target database via oracle net then use connection string as follows

$ rman target sys/syspassword@

You can also connect to RMAN in two steps first by invoking the rman

$ rman

The RMAN prompt appears

RMAN>

To connect to the target datbase..

RMAN> Connect target /
RMAN> Connect target sys/syspassword
RMAN> Connect target sys/syspassword@

Once you have connected to RMAN, you can start entering the commands. The commands can be typed in single line or in multiple lines and ends with a semicolon.

RMAN> Backup
2 database;

To add comments use the # symbol. Text after the # symbol in a line is interpreted as comments

RMAN> # Backup database
Backup database # this command will backup the database
include current controlfile; # backup control file along with database

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Remote_login_passwordfile

The password file is used to authenticate the users connecting to the database as Sysdba or Sysoper. The password file is created with the orapwd utility as follows,

$ cd $ORACLE_HOME/dbs
$ orapwd file=orapw password= entries=

Where,
file = the filename where the password is stored.
password = the password for sys user
entries = the number of users that can connect as sys user at a time. This parameter is optional.

Once the password file is created you need to set the init parameter remote_login_passwordfile for the database to use it.

The possible values for the parameter is

EXCLUSIVE - Only one database can use the password file. Multiple users can exist in the password file.

SHARED - More than one database can use the password file. However only Sys users allowed to have sysdba privilege. You will receive ORA-01999 error when you grant sysdba privilege to other users.

NONE - The password file is not used.

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ASM Views

The following V$views are used for managing ASM.

View Name	Description	Instance
V$ASM_DISKGROUP	Diskgroups discovered by ASM	DB
V$ASM_DISK	Disks discovered by ASM including disks that are not part of any Diskgroup.	DB
V$ASM_FILE	ASM files mounted by ASM instance	ASM
V$ASM_ALIAS	Filename alias of the ASM Files	ASM
V$ASM_OPERATION	Long running ASM operations	ASM
V$ASM_TEMPLATE	Template present in diskgroup	DB
V$ASM_CLIENT	Lists one row per each ASM instance for which the database instance has any open ASM files	DB

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Drop a file from diskgroup

Syntax

ALTER DISKGROUP diskgroup_name DROP FILE ‘filename’, ‘filename’..;

Note: ASM drops all the aliases associated with the filename.

Example 1

SQL> Alter Diskgroup ASMDATA DROP FILE ‘+ASMDB/gcprod/datafile/users.259.661355087’ , ‘+ASMDB/gcprod/datafile/sysaux.257.661355085’;

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Manage ASM Directories

In order to use ASM filename aliases, you need to create Directories.

Syntax:

To add directory
ALTER DISKGROUP diskgroup_name ADD DIRECTORY ‘filename’, ‘filename’..;

To rename directory
ALTER DISKGROUP diskgroup_name RENAME DIRECTORY ‘old_dirname’ TO ‘new_dirname’, ‘old_dirname’ TO ‘new_dirname’..;

To drop directory
ALTER DISKGROUP diskgroup_name DROP DIRECTORY ‘filename’ [FORCE or NOFORCE], ‘filename’ [FORCE or NOFORCE]..;

Where,

FORCE – To drop the directory even if it contains any alias definitions.
NOFORCE – It will not drop the directory if it contains any alias definitions

Example 1 (Add directory)

SQL> Alter Diskgroup asmdata ADD DIRECTORY ‘+ASMDATA/datafile’;

Example 2 (Rename directory)

SQL> Alter Diskgroup asmdata RENAME DIRECTORY ‘+ASMDATA/datafile’ TO ‘+ASMDATA/indexfile’;

EXAMPLE 3 (Drop directory)

SQL> Alter Diskgroup asmdata DROP DIRECTORY ‘+ASMDATA/indexfile’ FORCE;

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Mounting and Dismounting a Diskgroup

Diskgroups are automatically mounted at ASM instance startup and dismounted at ASM instance shutdown. To manually mount and dismount the diskgroups use the following statements,

Syntax:

ALTER DISKGROUP ALL or diskgroup_name MOUNT or DISMOUNT;

Example 1 (Mount a specific diskgroup)

SQL> Alter Diskgroup ASMIND Mount;

Example 2 (Dismount all diskgroups)

SQL> Alter Disgroup ALL DisMount;

Note

In the case of High and Normal Redundancy diskgroups you need all set of extents available for the diskgroups to mount. The unavailable disks may be used for redundant copies and you may mount the diskgroups without those disks. If there are sufficient disks available for the diskgroups to mount you can use the force option to mount it.

Alter Diskgroup diskgroup_name Mount Force;

The unavailable disks are taken offline. ASM drops those disks after the DISK_REPAIR_TIME expires.

In RAC ASM environments, you cannot MOUNT FORCE a disk group that is already mounted by another instance because the disks have been accessed by another instance and the disks are not locally accessible.

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Checking a Diskgroup

It checks the internal consistency of the diskgroup metadata. If any errors are found they are reported in the alert log.

Instance: ASM Instance
Privilege: Sysdba

Syntax

ALTER DISKGROUP diskgroup_name CHECK check_diskgroup_clause [REPAIR or NOREPAIR]

Where,

Check_dikgroup_clause= [ALL] or [DISK diskname] or [DISKS IN FAILGROUP failgroup_name] [FILE filename]

REPAIR = ASM attempts to repair any errors.
NOREPAIR= ASM reports the error in the alert log and does not attempt to repair it.

Example 1 (checks all the disks in the diskgroup)

SQL> Alter Diskgroup ASMDATA CHECK ALL;

Example 2 (checks only specific disks in the diskgroup)

SQL> Alter Diskgroup ASMIND CHECK
DISK data_05,
DISK data_06 NOREPAIR;

Example 3 (Checks all the disks in the failure group).

SQL> Alter Diskgroup ASMDATA CHECK
DISKS IN FAILGROUP ctrl_1;

Example 4 (checks specific files in the diskgroup)

SQL> Alter Diskgroup ASMIND CHECK
FILE ‘+ASMDB/gcprod/datafile/users.259.661355087’,
FILE ‘+ASMDB/gcprod/datafile/sysaux.257.661355085’;

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Rebalance a Diskgroup

Instance: ASM Instance
Privilege: Sysdba

Syntax

ALTER DISKGROUP diskgroup_name rebalance_diskgroup_clause

Where,

Rebalance_diskgroup_clause = REBALANCE POWER integer WAIT/NOWAIT
Integer – 0 to 11. If you omit ASM takes the value from ASM_POWER_LIMIT init parameter.
WAIT – The control is not returned to the user until the rebalance operation completes.
NOWAIT – The control immediately returns to the user and the rebalance operation takes place at the background and user can continue to do other operation.

Example 1

SQL> Alter Diskgroup ASMDATA REBALANCE POWER 10 wait;

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Resize a Disk

Note: Resizing disks in a diskgroup invokes implicit rebalancing of all the disks within the diskgroup.

Instance: ASM Instance
Privilege: Sysdba

Syntax

ALTER DISKGROUP diskgroup_name RESIZE resize_disk_clause rebalance_diskgroup_clause

Where

resize_disk_clause =[ALL SIZE size_clause] or [DISK diskname SIZE size_clause] or [DISKS IN FAILGROUP failgroup_name SIZE size_clause]

Note: If you omit the size clause then ASM uses the size returned by the OS.

Rebalance_diskgroup_clause = REBALANCE POWER integer WAIT/NOWAIT
Integer – 0 to 11. If you omit ASM takes the value from ASM_POWER_LIMIT init parameter.
WAIT – The control is not returned to the user until the rebalance operation completes.
NOWAIT – The control immediately returns to the user and the rebalance operation takes place at the background and user can continue to do other operation.


Example 1 (resizes all the disks in the diskgroup)

SQL> Alter Diskgroup ASMDATA RESIZE ALL SIZE 100G;

Example 2 (resizes only specific disks in the diskgroup)

SQL> Alter Diskgroup ASMIND RESIZE
DISK data_05 SIZE 100G,
DISK data_06
REBALANCE POWER 5;

Example 3 (resizes only specific disks in the failure group).

SQL> Alter Diskgroup ASMDATA RESIZE
DISKS IN FAILGROUP ctrl_1 SIZE 100G;

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Undrop Disk from Diskgroup

Note: To undrop a disk, the header_status from v$asm_disk view must be dropping. You cannot undrop a completely dropped disk.

Instance: ASM Instance
Privilege: Sysdba

Syntax

ALTER DISKGROUP [ALL/diskgroupname, diskgroupname..] UNDROP DISKS

Example 1

SQL> Alter Diskgroup asmdata undrop disks;

Example 2

SQL> Alter Diskgroup ALL undrop disks;

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