Terminology

HMC - Hardware Management Console - Device used to manage DS8k resources
HA - Host Adapter
DA - Device Adapter (Disks)
DDM - Disk Drive Module
16 Pack - 16 drives, minimum disk upgrade or installation is 16
CEC - Central Electronics Complex (Power System / Servers)
Storage Complex - 1 or more DS8k's managed by a single HMC or S-HMC
Storage Facility - Single DS8k unit (base frame and any expansion frames).
Logical PARtition (LPAR) - Uses software and firmware to logically partition resources on a system.
Storage Facility Image (SFI) - Logical DS8k, consists of 2 LPARs ESS01 and ESS11, clustered together.
Array site - Group of 8 DDMs selected by the DS8k, managed by 1 storage facility image
Array - Each array site can be individually formatted by the user to a specific RAID format. A formatted array site is called an array. Supported RAID formats are RAID-5, and RAID-10
Logical Volume - Composed of a set of extents from one extent pool. A logical volume composed of fixed block extents is called a LUN, if it composed of CKD extents it's referred to as a CKD volume or logical device
Volume Group - Grouping of LUNs, these LUNs are masked and presented to the host(s), one LUN can be in multiple volume groups and one volume group can be assigned to several host attachments.