Oracle ASM

A brief discussion on Oracle ASM and some of its advantages over other file systems.




Database centric file system
only used for managing database files
High performance
Requires a certain amount of tuning
Not suitable for all applications
Current recommendation is to allow ASM handle raid mirroring rather than let hardware handle it
Probably shouldn’t actually replace hardware raid with it.
ASM is now a mature technology with 11g and 12c
Unofficial benchmarks suggest that ASM is lightning fast, especially once tuned.
Requires very little actual interaction for the dbas.
There is practically no difference at all from within the rdbms
ASM replaces the physical storage level for ‘database files’
     datafiles, tempfiles, online logfiles, controlfile
     Recovery related files and the FRA
     spfile and passwordfile (12c)
Non database files (conventional storage)
     ADR files
The problem with o/s managed filesystems tends to be wasted IO
ASM reduces fragmentation and allows you to optimize allocation units thereby reducing IO wastage.

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