HP StorageWorks Scalable File Share System Installation and Upgrade Guide Version 2.2

Configuring the storage5–2
5.1 EVA4000 storage — overview and planning
This section contains a description of EVA4000 storage concepts and provides some examples to help you
to plan your storage configuration. This section is organized as follows:
• EVA4000 storage concepts (Section 5.1.1)
• EVA4000 configuration rules for HP SFS systems (Section 5.1.2)
• Assigning and sizing LUNs on EVA4000 storage (Section 5.1.3)
5.1.1 EVA4000 storage concepts
The EVA4000 array is a high-performance redundant array of independent disks (RAID) system that is
accessible from the administration server, the MDS server, and the Object Storage Servers through a storage
array network (SAN).
Before configuring the storage on the EVA4000 arrays in the HP SFS system, you should be familiar with
the following concepts in relation to EVA4000 arrays:
Array
An array is a complete EVA4000 system, comprised of controllers, disk shelves, and disks. Each
array is uniquely identified by a world-wide ID (WWID), which is a 16–character string. To
simplify displays, the HP SFS system assigns a simple array number to each array. This array
number is unique within the HP SFS system—unlike the WWID, which is unique across all RAID
arrays from any vendor. Array numbers are assigned as the system discovers an array; there is
no implicit order or relationship between array numbers.
Array controllers
An array controller is responsible for managing access to disk devices. Each array has dual
redundant controllers. Both controllers can be used at the same time; however, if one controller
fails, the other controller automatically takes over. A controller is uniquely identified by its serial
number.
Disk groups
A disk group is a set or pool of physical disks in which virtual disks, which are used as LUNs
(see the description of Logical Units (LUNs) and Virtual Disks) in the HP SFS system, are created.
A disk group must have a minimum of eight physical disk drives. A physical disk drive belongs to
only one disk group. One disk group (the default disk group) is created when the EVA4000
array is initialized. You must create an additional disk group; this task is explained in
Section 5.2.4.3.
Host Bus Adapter (HBA)
An HBA is an adapter that is used to connect the server to the storage area network. The HBA is
used to perform I/O operations on a LUN. Each HBA has two ports, and each HBA port has a
unique WWID.
Host
On the SAN, hosts are used to represent the HBA ports on the servers (see the description of
Host Bus Adapter). Each host represents four HBA ports (that is, two HBA ports on each of the
two servers in a server pair). To allow a server pair to access a virtual disk, you present the
virtual disk as a LUN to the host associated with the server pair. See the description of Logical
Units (LUNs) and Virtual Disks.