Database setup: the Oracle Automatic Storage Manager
The Automatic Storage Manager (ASM) is the Oracle storage management program. It is part of the Oracle 11g package and must be installed as part of the Oracle grid architecture.
From the user space view ASM is similar to a raw device, because the data "files" are only accessible via the application tools, they cannot be accessed via the normal file system access. ASM manages the full disk storage, including striping the storage over several disks.
The ASM disks and disk groups were managed by the ASM Configuration Assistant (asmca) for both disk types DASD and FCP. It is also possible to perform ASM tasks by using asmcmd at the command line in the same Oracle HOME, or by using sqlplus to control ASM.
To prepare the disks for ASM, the disks were partitioned and added to ASM disk groups. DASD devices are low-level formatted first of all.