As a result, this requires all read-write tablespaces to also be locally
managed.
In the first part of this chapter, I??™ll review some of the common problems and solutions when
using traditional disk space management using a file system on a database server. In the second
half of the chapter, I??™ll present an overview of Automatic Storage Management (ASM), a built-in
logical volume manager that eases administration, enhances performance, and improves availability.
Traditional Disk Space Storage
In lieu of using a third-party logical volume or Oracle??™s Automatic Storage Management
(discussed later in this chapter), you must be able to manage the physical datafiles in your
database to ensure a high level of performance, availability, and recoverability. In general, this
means spreading out your datafiles to different physical disks. In addition to ensuring availability
by keeping mirrored copies of redo log files and control files on different disks, I/O performance
is improved when users access tables that reside in tablespaces on multiple physical disks instead
of one physical disk. Identifying an I/O bottleneck or a storage deficiency on a particular disk
volume is only half the battle; once the bottleneck is identified, you need to have the tools and
knowledge to move datafiles to different disks. If a datafile has too much space or not enough
space, resizing an existing datafile is a common task.
In this section, I??™ll discuss a number of different ways to resize tablespaces, whether they are
smallfile or bigfile tablespaces.
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