HP 3PAR InForm OS 3.1.1 Concepts Guide

Figure 1 HP 3PAR Storage System Data Layers
Physical Disks
A physical diskis a hard drive mounted on a drive magazine located in an HP 3PAR Storage
System drive cage. For more information about physical disks and the HP 3PAR Storage System
hardware platforms, see “HP 3PAR Storage System Hardware” (page 58).
Chunklets
Physical disks are divided into chunklets. Each chunklet occupies contiguous space on a physical
disk. On F-Class and T-Class systems all chunklets are 256 MB. On P10000 systems all chunklets
are 1 GB. Chunklets are automatically created by the HP 3PAR InForm
®
Operating System and
they are used to create logical disks. A chunklet is assigned to only one logical disk. For more
information about chunklets, see “Chunklets” (page 33).
Logical Disks
A logical disk is a collection of physical disk chunklets arranged as rows of RAID sets. Each RAID
set is made up of chunklets from different physical disks. Logical disks are pooled together in
Common Provisioning Groups (CPGs) which allocate space to virtual volumes. The underlying
logical disks are automatically created by the InForm OS when you create CPGs. The RAID type,
3PAR Storage Concepts and Terminology 13