The OMF-related initialization parameters are detailed in Table 6-1. Note that the operating
system path specified for any of these initialization parameters must already exist; Oracle will not
create the directory. Also, these directories must be writable by the operating system account that
owns the Oracle software (which on most platforms is oracle).
Bigfile Tablespaces
Bigfile tablespaces, introduced in Oracle 10g, take OMF files to the next level; in a bigfile tablespace,
a single datafile is allocated, and it can be up to 8EB (exabytes, a million terabytes) in size.
Bigfile tablespaces can only be locally managed with automatic segment space management.
If a bigfile tablespace is used for automatic undo or for temporary segments, then segment space
management must be set to MANUAL.
Bigfile tablespaces can save space in the System Global Area (SGA) and the control file because
fewer datafiles need to be tracked; similarly, all alter tablespace commands on bigfile tablespaces
need not refer to datafiles because one and only one datafile is associated with each bigfile
tablespace. This moves the maintenance point from the physical (datafile) level to the logical
(tablespace) level, simplifying administration. One downside to bigfile tablespaces is that a
Initialization Parameter Description
DB_CREATE_FILE_DEST The default operating system file directory where
datafiles and tempfiles are created if no pathname
is specified in the create tablespace command.
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