SVS200 (T1714-96008, June 2006)

18 Overview of LUN Manager

You can connect the array to open-system server hosts on different platforms (for example, UNIX and PC

servers). To configure a system that includes open-system hosts and an array, you must use LUN Manager

to configure logical volumes and ports.

One of the important tasks with logical volume configuration is to define I/O paths from hosts to logical

volumes. If paths are defined, hosts can send commands and data to logical volumes and receive data

from logical volumes.

After the system begins operating, you might need to modify the system configuration. For example, if you

add hosts or disks, you must add I/O paths. Even when the system is operating, you can use LUN

Manager to modify the system configuration. You do not need to reboot the system when changing the

system configuration.

NOTE: Throughout this user guide, logical volumes are sometimes referred to as logical devices (LDEVs).

Configuring LU paths

Use LUN Manager to make various settings for logical volumes (LUs), including LU path settings. When

you configure a system, you must define LU paths to let hosts transfer data to and from storage.

CAUTION: When defining LU paths, you must not use RAID Manager XP and XP Remote Web Console

at the same time.

Configuring LU paths in Fibre Channel environments

After open-system hosts and the array are physically connected by cables, hubs, and so on, you must use

LUN Manager to establish I/O paths between the hosts and logical volumes. This defines which host can

access which logical volume. Logical volumes that open-system hosts can access are referred to as logical

units (LUs). Paths between open-system hosts and LUs are referred to as LU paths.

Before defining LU paths, you must classify server hosts by host groups. For example, if Linux and

Windows hosts are connected to the array, you must create one host group for Linux hosts and another

host group for Windows hosts. Then you must register the host bus adapters for Linux hosts in the Linux

host group. You must also register the host bus adapters for Windows hosts in the Windows host group.

Host groups can contain only hosts connected to the same port, and cannot contain hosts connected to

different ports. For example, if two Windows hosts are connected to port 1A and three Windows hosts

are connected to port 1B, you cannot register all five Windows hosts in one host group. You must register

the first two Windows hosts in one host group and register the remaining three Windows hosts in another

host group.