Raid Manager Command Devices - HP StorageWorks XP128 User Manual

If LUN security is disabled, the hosts will not be able to access most of the LUs. Hosts will have access to
only those LUs defined in host group 0.
By default, LUN security is disabled on a port, so host group 0 is the only accessible host group reserved
for the port. Initially it contains no LUs or WWNs.
When security is disabled, only LUs defined in host group 0 are accessible to hosts connected to the port,
regardless of any WWNs that may be defined for a host group. After security is enabled, WWNs are
used, permitting or restricting access based on WWN.
If you have more than one host group defined on a port, you can locate host group 0 by disabling LUN
security from the port. When done, the tree display will "gray" out all host groups except host group 0.

RAID Manager command devices

To use RAID Manager commands for Business Copy XP and Continuous Access XP operations, you must
designate at least one LDEV on the disk array as a command device. A command device receives RAID
Manager commands entered from hosts. When you enter a RAID Manager command from a host, the
command is transferred to the target device via the command device.
If you want to restrict access to LUs and by RAID Manager, you can apply command device security in LUN
Manager.
Restrictions
You cannot use the following LDEVs as command devices:
• Volumes that do not have read/write access
• Volumes reserved by Auto LUN XP
• Continuous Access XP volumes
• BC volumes
• External LUs
• iSCSI volumes (volumes to which paths are defined from iSCSI ports)
• Flex Copy XP volumes
You cannot use an LDEV as a command device if a path is defined between an iSCSI port and the LDEV.
If you want to use a LUSE volume as a command device, you must specify only the first LU as the command
device.
Fibre Channel port attributes
In Fibre Channel environments, you must configure the Fibre Channel topology and set addresses for the
Fibre Channel ports. You can enhance system performance by adjusting the data transfer speed at the
Fibre Channel ports and changing the channel adapter mode.
Fibre Channel topologies
Fibre Channel provides the following topologies:
• Fabric: Uses a fabric switch to connect a large number of devices. Each device has the full bandwidth
of 100 MB/sec.
• FC-AL (Fibre Channel-Arbitrated Loop): A shared-bandwidth topology that can connect up to 126
devices (AL ports).
• Point-to-point: A simple Fibre Channel topology in which two devices are connected directly.
When configuring the disk array, use LUN Manager to specify whether the hosts and the disk array are
connected by a fabric switch. Also, you must specify FC-AL or point-to-point in the LUN Manager pane. The
default is FC-AL.
If you are using a fabric switch, consult the switch's documentation to learn whether FC-AL or point-to-point
should be used. Some fabric switches require that you specify point-to-point to get the system running.
20 LUN Manager for the XP128/XP1024