Capacities

Depending on the context, the term capacity can refer to logical space or to actual, physical space.

Note: Drive manufacturers often report drive capacities in decimal units (powers of 10). An Oracle FS System reports the capacity of physical storage and the size of logical volumes in binary units (powers of two):

1 MB = 1024² (1,048,576) bytes
1 GB = 1024³ (1,073,741,824) bytes
1 TB = 1024⁴ (1,099,511,627,776) bytes

Logical capacity

The space that you request that the system set aside for a logical volume. In Oracle FS System Manager (GUI), logical capacities are used in the following contexts:

addressable: The size limit that you established for the volume. The addressable capacity is sometimes referred to as the maximum size of a volume. Addressable capacity includes the space that is needed for the repository when you specify clone-based data protection for the volume.
allocated: The amount of space that the system has set aside for a specific volume.
used: The amount of the allocated space in a filesystem that contains user data.

Note: Logical capacities do not include the overhead that is needed for implementing RAID protection (parity data and mirroring).

Physical capacity

The actual space that the system assigns to the volume or has available for assignment. Values that the system reports for physical capacities refer to the actual space on the physical media.

The value that is reported for the physical capacity of a volume is greater than the value that is reported for the logical capacity of the volume. The physical capacity of a volume is greater because of the overhead that is used to implement the volume. For example, the physical capacity takes into account the space that is needed for the clones of the volume and for RAID protection.