The single
datafile can be up to 128TB (terabytes) in size if the tablespace block size is 32KB. Many of the
commands previously available only for maintaining datafiles can now be used at the tablespace
level if the tablespace is a bigfile tablespace. Chapter 6 reviews how bigfile tablespaces are created
and maintained.
FIGURE 3-4 Using EM Database Control to edit temporary tablespace groups
68 Oracle Database 11g DBA Handbook
The maintenance convenience of bigfile tablepsaces can be offset by some potential
disadvantages. Because a bigfile tablespace is a single datafile, a full backup of a single large
datafile will take significantly longer than a full backup of several smaller datafiles (with the same
total size as the single bigfile tablespace) because Oracle only uses one slave process per datafile
and therefore cannot back up different parts of a bigfile tablespace using parallel processes. If
your bigfile tablespaces are read-only or only changed blocks are backed up on a regular basis,
the backup issue may not be critical in your environment.
Optimal Flexible Architecture
Oracle??™s Optimal Flexible Architecture (OFA) provides guidelines to ease the maintenance of the
Oracle software and database files as well as improve the performance of the database by placing
the database files such that I/O bottlenecks are minimized.
Although using OFA is not strictly enforced when you??™re installing or maintaining an Oracle
environment, using OFA makes it easy for someone to understand how your database is organized
on disk, preventing that phone call in the middle of the night during the week you??™re on vacation!
OFA is slightly different depending on the type of storage options you use??”either an Automatic
Storage Management (ASM) environment or a standard operating system file system that may or
may not be using a third-party logical volume manager or RAID-enabled disk subsystem.
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