ASMCMD is a utility that can be used to manage ASM (Automatic Storage Management) diskgroups. This utility uses familiar Unix-style filesystem commands to view and manage ASM files and directories.
In Oracle 10g Release 1, ASM could only be administered through SQL commands or the Enterprise Manager (EM) GUI. For example, to list the diskgroups one would typically open EM or connect to sqlplus and issue a SELECT against some V$ASM_* views (like V$ASM_DISKGROUP and V$ASM_DISK). This utility allows people that is not familiar with SQL to view and manage ASM without opening any GUI tools.
ASM was first released with Oracle 10g Release 2.
Under the covers
Asmcmd is implemented as a shell script that starts a Perl program called asmcmdcore. If you are a Perl programmer, you can easily extend this script to add additional commands and security checks.
The ASM Command Line Utility can be started by executing the asmcmd command. Here is a Linux/Unix example:
$ export ORACLE_SID=+ASM $ cd $ORACLE_HOME/bin $ asmcmd ASMCMD> exit $
The asmcmd utility also provides a useful "-p" option that will display the current path in the prompt. Here is an example:
$ asmcmd -p ASMCMD [+] > cd FLASH ASMCMD [+FLASH] >
Some of the more interesting commands are described below -
Getting some help:
Help for a spesific command:
ASMCMD> help ls
Navigating through the structure using "cd", "ls" and "pwd" commands:
ASMCMD> ls -l State Type Rebal Unbal Name MOUNTED EXTERN N N DISKGROUP1/ MOUNTED EXTERN N N FLASH/ ASMCMD> cd DISKGROUP1 ASMCMD> ls -l Type Redund Striped Time Sys Name Y SALES/ ASMCMD> cd SALES ASMCMD> ls -l Type Redund Striped Time Sys Name Y CONTROLFILE/ Y DATAFILE/ Y ONLINELOG/ Y PARAMETERFILE/ Y TEMPFILE/ N spfilesales.ora => +DISKGROUP1/SALES/PARAMETERFILE/spfile.268.569267897 ASMCMD> cd DATAFILE ASMCMD> pwd +DISKGROUP1/SALES/DATAFILE
ASMCMD> find / spfile* +DISKGROUP1/SALES/PARAMETERFILE/spfile.268.569267897 +DISKGROUP1/SALES/spfilesales.ora
List all connected instances:
ASMCMD> lsct DB_Name Status Software_Version Compatible_version Instance_Name sales CONNECTED 10.2.0.1.0 10.2.0.1.0 sales1 sales CONNECTED 10.2.0.1.0 10.2.0.1.0 sales2
List all diskgroups:
ASMCMD> lsdg State Type Rebal Unbal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Name MOUNTED EXTERN N N 512 4096 1048576 11264 9885 0 9885 0 DISKGROUP1/ MOUNTED EXTERN N N 512 4096 1048576 10240 9906 0 9906 0 FLASH/
Check used space:
ASMCMD> du Used_MB Mirror_used_MB 1523 1523
Delete files (be careful!!!):
ASMCMD> rm * Are you sure? (y/n) y
Metadata (ASM superblocks) backup and recovery (Oracle 11g and above):
ASMCMD> md_backup –b /tmp/dg.backup –g DATA –g RECOVER ASMCMD> md_restore –t full –g RECOVER /tmp/dg.backup