Database Block Size

Minimum

2048 bytes; must be a multiple of operating system physical block size

Maximum

Operating system dependent; never more than 32 KB

Database Blocks

Minimum in initial extent of a segment.

2 blocks

Maximum per datafile

Platform dependent; typically 222-1 blocks

Controlfiles

Number of control files

1 minimum; 2 or more (on separate devices) strongly recommended

Size of a control file

Dependent on operating system and database creation options; maximum of 20,000 x (database block size)

Database files

Maximum per tablespace

Operating system dependent; usually 1022

Maximum per database

65533

May be less on some operating systems

Limited also by size of database blocks and by the DB_FILES initialization parameter for a particular instance

Database extents

Maximum

4 GB, regardless of the maximum file size allowed by the operating system

Database file size

Maximum

Operating system dependent. Limited by maximum operating system file size; typically 22² or 4M blocks

Default value

Derived from tablespace default storage or DB_BLOCK_SIZE initialization parameter

Maximum

Unlimited

Redo Log Files

Maximum number of logfiles

Limited by value of MAXLOGFILES parameter in the CREATE DATABASE statement

Control file can be resized to allow more entries; ultimately an operating system limit

Maximum number of logfiles per group

Unlimited

Redo Log File Size

Minimum size

50 KB

Maximum size

Operating system limit; typically 2 GB

Tablespaces

Maximum number per database

64 K

Number of tablespaces cannot exceed the number of database files, as each tablespace must include at least one file