About ASMCMD

System-Generated Filename or Fully Qualified Filename

Every file created in Oracle ASM gets a system-generated filename, otherwise known as a fully qualified filename. This is the same as a complete path name in a local file system.

Oracle ASM generates filenames according to the following scheme:

+diskGroupName/databaseName/fileType/fileTypeTag.fileNumber.incarnation

An example of a fully qualified filename is the following:

+data/orcl/CONTROLFILE/Current.256.541956473

In the previous fully qualified filename, data is the disk group name, orcl is the database name, CONTROLFILE is the file type, and so on.

Only the slash (/) is supported by ASMCMD. Filenames are not case sensitive, but are case retentive. If you type a path name as lowercase, ASMCMD retains the lowercase.

For more information about Oracle ASM filenames, refer to "Fully qualified File Name Form".

Directory

As in other file systems, an Oracle ASM directory is a container for files, and an Oracle ASM directory can be part of a tree structure of other directories. The fully qualified filename represents a hierarchy of directories in which the plus sign (+) represent the root directory. In each disk group, Oracle ASM automatically creates a directory hierarchy that corresponds to the structure of the fully qualified filenames in the disk group. The directories in this hierarchy are known as system-generated directories.

ASMCMD enables you to move up and down in this directory hierarchy with the cd (change directory) command. The ASMCMD ls (list directory) command lists the contents of the current directory, while the pwd command prints the name of the current directory.

When you start ASMCMD, the current directory is set to root (+). For an Oracle ASM instance with two disk groups, for example, data and fra, entering an ls command with the root directory as the current directory produces the following output:

The following example demonstrates navigating the Oracle ASM directory tree (refer to the fully qualified filename shown previously):

You can create your own directories as subdirectories of the system-generated directories using the ASMCMD mkdir command. The directories that you create can have subdirectories, and you can navigate the hierarchy of both system-generated directories and user-created directories with the cd command.

The following example creates the directory mydir under orcl in the disk group data:

ASMCMD> mkdir +data/orcl/mydir

If you start ASMCMD with the -p flag, then ASMCMD shows the current directory as part of its prompt. See "Including the Current Directory in the ASMCMD Prompt".

ASMCMD retains the case of the directory that you entered.

Alias

Aliases are filenames that are references or pointers to system-generated filenames. However, aliases are user-friendly names. Aliases are similar to symbolic links in UNIX or Linux computers. You can create aliases to simplify Oracle ASM filename administration. You can create aliases with the mkalias ASMCMD command or a SQL ALTER DISKGROUP command.

An alias has at a minimum the disk group name as part of its complete path. You can create aliases at the disk group level or in any system-generated or user-created subdirectory. The following are examples of aliases:

If you run the ASMCMD ls (list directory) with the -l flag, each alias is listed with the system-generated file to which the alias refers.

ctl1.f => +data/orcl/CONTROLFILE/Current.256.541956473

For more information about aliases, refer to "Alias Oracle ASM Filename Forms".

Absolute Path and Relative Path

When you run an ASMCMD command that accepts a filename or directory name as an argument, you can use the name as either an absolute path or a relative path.

An absolute path refers to the full path of a file or directory. An absolute path begins with a plus sign (+) followed by a disk group name, followed by subsequent directories in the directory tree. The absolute path includes directories until the file or directory of interest is reached. A complete system-generated filename, otherwise known as the fully qualified filename, is an example of an absolute path to a file.

Using an absolute path enables the command to access the file or directory regardless of where the current directory is set. The following rm command uses an absolute path for the filename:

ASMCMD [+] > rm +data/orcl/datafile/users.259.555341963

The following cd command uses an absolute path to the directory.

ASMCMD [+data/mydir] > cd +data/orcl/CONTROLFILE

A relative path includes only the part of the filename or directory name that is not part of the current directory. That is, the path to the file or directory is relative to the current directory.

In the following example, the rm command operates on the file undotbs1.272.557429239, which in this case is a relative path. ASMCMD appends the current directory to the command argument to obtain the absolute path to the file. In this example this is +data/orcl/DATAFILE/undotbs1.272.557429239.

Paths to directories can also be relative. You can go up or down the hierarchy of the current directory tree branch by providing a directory argument to the cd command whose path is relative to the current directory.

In addition, you can use the pseudo-directories "." and ".." in place of a directory name. The "." pseudo-directory is the current directory. The ".." pseudo-directory is the parent directory of the current directory.

The following example demonstrates how to use relative directory paths and pseudo-directories:

Wildcard Characters

The wildcard characters * and % match zero or more characters anywhere within an absolute or relative path, which saves typing of the full directory or file name. The two wildcard characters behave identically. There are various ASMCMD commands that accept wildcards. These include cd, du, find, ls, lsattr, lsdg, lsdsk, lsgrp, lsusr, and rm.

If a wildcard pattern matches only one directory when using wildcard characters with cd, then cd changes the directory to that destination. If the wildcard pattern matches multiple directories, then ASMCMD does not change the directory but instead returns an error.

Example 12-1 illustrates the use of wildcards.

ASMCMD [+] > cd +data/orcl/*FILE
ASMCMD-08005: +data/orcl/*FILE: ambiguous

ASMCMD [+] > cd +data/orcl/C*
ASMCMD [+data/orcl/CONTROLFILE] >

ASMCMD [+] > ls +fra/orcl/A%
2009_07_13/
2009_07_14/

ASMCMD [+] >  ls +fra/orcl/ARCHIVELOG/2009%

+fra/orcl/ARCHIVELOG/2009_07_13/:
thread_1_seq_3.260.692103543
thread_1_seq_4.261.692108897
thread_1_seq_5.262.692125993
thread_1_seq_6.263.692140729
thread_1_seq_7.264.692143333
 
+fra/orcl/ARCHIVELOG/2009_07_14/:
thread_1_seq_8.271.692158265
thread_1_seq_9.272.692174597

ASMCMD [+] > ls data/orcl/*

+data/orcl/CONTROLFILE/:
Current.260.692103157

+data/orcl/DATAFILE/:
EXAMPLE.265.692103187
SYSAUX.257.692103045
SYSTEM.256.692103045
UNDOTBS1.258.692103045
USERS.259.692103045

+data/orcl/ONLINELOG/:
group_1.261.692103161
group_2.262.692103165
group_3.263.692103169

+data/orcl/PARAMETERFILE/:
spfile.266.692103315

+data/orcl/TEMPFILE/:
TEMP.264.692103181
spfileorcl.ora

Running ASMCMD Without Any Options

To run ASMCMD in interactive mode without any options:

1. Enter the following at the operating system command prompt:

   asmcmd

   Oracle displays an ASMCMD command prompt as follows:

   ASMCMD>

2. Enter an ASMCMD command and press Enter. The command runs and displays its output, if any, and then ASMCMD prompts for the next command.

3. Continue entering ASMCMD commands until you have completed the tasks.

4. Enter the exit or quit command to exit ASMCMD.

Specifying the Type of Connection

You can specify the -a option to choose the type of connection, either SYSASM or SYSDBA. The default value is SYSASM and should be used when administering an Oracle ASM instance. Connect as SYSDBA when connecting to the database instance.

For example:

$ asmcmd -a sysasm

Specifying the Verbose Mode

You can specify the -v option with the asmcmd command to display additional information with some commands to help users diagnose problems as shown in the following example:

Including the Current Directory in the ASMCMD Prompt

You can specify the -p option with the asmcmd command to include the current directory in the ASMCMD prompt as shown in the following example:

Displaying the ASMCMD Version Number

You can specify the -V option when starting asmcmd to displays the asmcmd version number. After displaying the version number, asmcmd immediately exits.

For example: