Partition
Partitions are sections on a LUN. Each LUN can have a maximum of four partitions. Each partition can either have space allocated to it or be empty. When a LUN is first created, all of the available space is located in the first partition, while the other three partitions are empty. Each partition can “contain” only one file volume.
File Volume
File volumes are organized amounts of available storage space and are created from partitions. The file volume is the space where the user stores information. If the volume does not use up all of the available space in a partition, the remaining space is automatically allocated to the next partition. After four volumes are created on a LUN, any remaining space is inaccessible.
Segment
A segment is a portion of a partition that can be attached to an existing file volume to increase its size. Segments can be “attached” to an existing file volume at any time. If a file volume is nearly full, attaching a segment gives the users more space to store data in. See “How to Attach Segments” on page 20 for more information.
How to Create File Volumes and Segments
Every new file volume is limited to 255GB in size. If you want a larger file volume, create one primary volume and up to 63 segments per LUN. Then attach the segment(s) to the primary volume to increase its size. For more information about attaching segments, refer to “How to Attach Segments” on page 20.