Since Oracle announced Automatic Storage Management (ASM) as a new feature in Oracle Database 10g, advocates of Oracle technology quickly realized that the filesystem as they knew it for storing database files may be replaced by ASM. DBAs and system administrators alike asked the same question: What is the benefit of ASM? You should consider ASM for your corporate infrastructure for a number of reasons. ASM, in a nutshell, provides an integrated filesystem and volume management in the database kernel. Here are the most important reasons why you should consider ASM:
Raw device performance
Logical volume management
Consolidation of storage management
Mirroring/triple mirroring equivalence ...