ctl
SQL>
Similarly, you can use the Linux utility asmcmd to make copies of the control file from one
disk group to another, and change the CONTROL_FILES parameter to reflect the new control file
location. I present an overview of the asmcmd command later in this chapter.
Automatic Storage Management
In Chapter 3, we presented some of the file naming conventions used for ASM objects. In this
section, I??™ll delve more deeply into how we can create tablespaces??”and ultimately datafiles
behind the scenes??”in an ASM environment with one or more disk groups.
When creating a new tablespace or other database structure, such as a control file or redo
log file, you can specify a disk group as the storage area for the database structure instead of an
operating system file. ASM takes the ease of use of Oracle-Managed Files (OMF) and combines
it with mirroring and striping features to provide a robust file system and logical volume manager
that can even support multiple nodes in an Oracle Real Application Cluster (RAC). ASM eliminates
the need to purchase a third-party logical volume manager.
ASM not only enhances performance by automatically spreading out database objects over
multiple devices, but also increases availability by allowing new disk devices to be added to the
database without shutting down the database; ASM automatically rebalances the distribution of
files with minimal intervention.
We??™ll also review the ASM architecture.
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