HP Surestore NAS 8000 Direct Attach Solution Integration Manual

6 Network and Storage Planning
Storage Overview and Terminology
The HP NAS 8000 is an easy-to-manage storage solution for heterogeneous environments
including Windows, UNIX, and Linux.
The storage space on the HP NAS 8000 is made up of physical and logical storage:
■
Physical storage refers to the hardware used for data storage.
■
Logical storage is created by software that organizes your physical storage into file
volumes and directories.
Work with the customer to construct an overall storage architecture determining the total
amount of storage available and how it should be allocated to different groups or functions.
Data protection, including two RAID levels and active spare settings, should also be
considered.
Physical Storage
The HP NAS 8000 Direct Attach solutions use either the HP Virtual Array 7100 or the HP
Virtual Array 7400 series high-performance, high-availability, multi-terabyte storage arrays.
Logical Storage
Virtual Array
The term “Virtual Array” refers to the way the disks within the array are treated as a pool of
data storage blocks instead of real physical disks.
Because data is spread across all of the disks in the array, logical-to-physical data maps keep
track of where the data is physically located on the disks in the array. These maps are stored in
array controller cache memory. The host has no visibility of the cache data maps; it is simply
presented with logical units (LUNs) for data storage operations.
Logical Unit Number
A logical unit number (LUN) is a logical aggregation of space on physical drives. LUNs are
unique identifiers that enable the controller to differentiate between separate devices (each of
which is a logical unit). Each LUN is a unique number that identifies a specific unit of storage.
The HP NAS 8000 supports up to 127 LUNs.
Volume Groups
A volume group is the aggregation of one or more LUNs. Volume groups combine the space
from LUNs and make the space accessible to the file system for creating file volumes and
directories, which can then be made accessible to users.
File Volumes
A volume group is divided into one or more file volumes. File volumes are the basic unit of
logical storage for a file system on the HP NAS 8000. File volumes can be further subdivided
into individual directories.