IBM System storage DS6000 Series, Attachment Manual

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The access-restricted mode prevents all fibre-channel-attached host systems
that do not have an access profile to access volumes that you defined in the
storage unit. This is the default mode.
Your IBM service support representative (SSR) can change the logical unit number
(LUN) access mode. Changing the access mode is a disruptive process. Shut down
and restart both clusters of the storage unit.
Access profiles
Any fibre-channel-attached host system that has an access profile can access only
those volumes that are defined in the profile. Depending on the capability of the
particular host system, an access profile can contain up to 256 or up to 4096
volumes.
The setup of an access profile is transparent to you when you use the IBM
TotalStorage DS Storage Manager to configure the hosts and volumes in the
storage unit. Configuration actions that affect the access profile are as follows:
v When you define a new fibre-channel-attached host system in the IBM
TotalStorage DS Storage Manager by specifying its worldwide port name
(WWPN), the access profile for that host system is automatically created. Initially
the profile is empty. That is, it contains no volumes. In this state, the host cannot
access any logical volumes that are already defined in the storage unit.
v When you add new logical volumes to the storage unit, the new volumes are
assigned to the host. The new volumes are created and automatically added to
the access profile.
v When you assign volumes to fibre-channel-attached hosts, the volumes are
added to the access profile.
v
When you remove a fibre-channel-attached host system from the IBM
TotalStorage DS Storage Manager, you delete the host and its access profile.
The anonymous host
When you run the storage unit in access-any mode, the IBM TotalStorage DS
Storage Manager displays a dynamically created pseudo-host called anonymous.
This is not a real host system connected to the storage server. It is intended to
represent all fibre-channel-attached host systems that are connected to the storage
unit that do not have an access profile defined. This is a reminder that logical
volumes defined in the storage unit can be accessed by hosts which have not been
identified to the storage unit.
Fibre-channel storage area networks
Fibre-channel storage area networks connect servers and storage devices.
A Fibre-channel storage area network (SAN) is a specialized, high-speed network
that attaches servers and storage devices. With a SAN, you can perform an
any-to-any connection across the network using interconnect elements such as
routers, gateways and switches. With a SAN, you can eliminate the connection
between a server, storage, and the concept that the server effectively owns and
manages the storage devices.
The SAN also eliminates any restriction to the amount of data that a server can
access. This restriction is limited by the number of storage devices that can be
attached to the individual server. Instead, a SAN introduces the flexibility of
Chapter 1. Introduction
17