Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

How the defragmentation utility works
Free resources are originally aligned in the most efficient order possible and are
allocated to files in a way that is considered by the system to provide optimal
performance. When a file system is active for extended periods of time, new files
are created, old files are removed, and existing files grow and shrink. Over time,
the original ordering of free resources is lost and the file system tends to spread
across the disk, leaving unused gaps or fragments between areas that are in use.
This process, known as fragmentation, leads to degraded performance because
the file system has fewer choices when selecting an extent (a group of contiguous
data blocks) to assign to a file. You should analyze the degree of fragmentation
before creating new database files.
VxFS provides the online administration utility fsadm to resolve fragmentation
problems. The utility can be run on demand and should be scheduled regularly
as a cron job.
How the resizing utility works
Changes in database size can result in file systems that are too large or too small
for the current database. Without special utilities, expanding or shrinking a file
system includes the following adminstrative operations: stopping applications,
offloading the contents of the file system, rebuilding the file system to a new size,
and then restoring the data. Data is unavailable to users while these administrative
tasks are performed.
The VxFS file system utility fsadm provides a mechanism to resize file systems
without unmounting them or interrupting users' productivity. Because the VxFS
file system can only be mounted on one device, expanding a file system means
that the underlying device must also be expandable while the file system is
mounted. Working with VxVM, VxFS provides online expansion capability.
About cross-platform data sharing
Veritas Cross-Platform Data Sharing allows data to be serially shared among
heterogeneous systems where each system has direct access to the physical devices
that hold the data. This feature can be used only in conjunction with Veritas
Volume Manager. Shared or parallel access is possible for read-only data.
Cross-Platform Data Sharing provides the fastest way to use Oracle's Transportable
Tablespace (TTS) feature for migrating databases to different platforms in Oracle
10g or for moving sets of tablespaces between databases on the same platform in
Oracle9.
See the Veritas Storage Foundation Cross-Platform Data Sharing Administrator's
Guide.
Introducing Veritas Storage Foundation for Oracle
How Veritas File System works
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