Connecting To and Starting Up an Oracle ASM Instance

You start an Oracle ASM instance similarly to the way in which you start an Oracle Database instance with some minor differences.

When starting an Oracle ASM instance, note the following:

  • To connect to a local Oracle ASM instance with SQL*Plus, set the ORACLE_SID environment variable to the Oracle ASM system identifier (SID).

    The default Oracle ASM SID for a single-instance database is +ASM, and the default SID for Oracle ASM for an Oracle RAC node is +ASMnode_number where node_number is the number of the node. The ORACLE_HOME environment variable must be set to the Grid Infrastructure home where Oracle ASM was installed.

    Note:

    Oracle recommends that you do not change the default Oracle ASM SID name.

  • The initialization parameter file must contain the following entry:

    INSTANCE_TYPE = ASM

    This parameter indicates that an Oracle ASM instance, not a database instance, is starting.

  • When you run the STARTUP command, rather than trying to mount and open a database, this command attempts to mount Oracle ASM disk groups.

    For information about disk groups that are mounted at startup time, see "About Mounting Disk Groups at Startup".

    After the Oracle ASM instance has started, you can mount disk groups with the ALTER DISKGROUP...MOUNT command. See "Mounting and Dismounting Disk Groups" for more information.

  • The associated Oracle Database instance does not have to be running when you start the associated Oracle ASM instance.

The following list describes how Oracle ASM interprets SQL*Plus STARTUP command parameters.

  • FORCE Parameter

    Issues a SHUTDOWN ABORT to the Oracle ASM instance before restarting it.

    If an Oracle Automatic Storage Management Cluster File System (Oracle ACFS) file system is currently mounted on Oracle ADVM volumes, the file system should first be dismounted. Otherwise, applications encounter I/O errors and Oracle ACFS user data and metadata may not be written to storage before the Oracle ASM storage is fenced. For information about dismounting an Oracle ACFS file system, see "Deregistering, Dismounting, and Disabling Volumes and Oracle ACFS File Systems".

  • MOUNT or OPEN Parameter

    Mounts the disk groups specified in the ASM_DISKGROUPS initialization parameter. This is the default if no command parameter is specified.

  • NOMOUNT Parameter

    Starts up the Oracle ASM instance without mounting any disk groups.

  • RESTRICT Parameter

    Starts up an instance in restricted mode that enables access only to users with both the CREATE SESSION and RESTRICTED SESSION system privileges. You can use the RESTRICT clause in combination with the MOUNT, NOMOUNT, and OPEN clauses.

    See Also:

    "About Restricted Mode" for more information

    In restricted mode, database instances cannot use the disk groups. In other words, databases cannot open files that are in that disk group. Also, the disk group cannot be mounted by any other instance in the cluster. Mounting the disk group in restricted mode enables only one Oracle ASM instance to mount the disk group. This mode is useful to mount the disk group for repairing configuration issues.

The following is a sample SQL*Plus session for starting an Oracle ASM instance.

SQLPLUS /NOLOG
SQL> CONNECT SYS AS SYSASM
Enter password: sys_password
Connected to an idle instance.

SQL> STARTUP
ASM instance started

Total System Global Area    71303168 bytes
Fixed Size                   1069292 bytes
Variable Size               45068052 bytes
ASM Cache                    25165824 bytes
ASM disk groups mounted

For more information about user authentication, see "Authentication for Accessing Oracle ASM Instances".

See Also: