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Configuring Your Library
From the operator panel, select Setup > I/O Blades > Host Management.
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From the Web client, select Setup > I/O Blades > Host Management.
Host Mapping - Overview
Host mapping enables you to manually modify host information and set logical unit number (LUN) mappings, and to map
specific hosts to library LUN devices.
I/O blades discover target devices that are attached to ports 3–6, as well as their internal virtual port (see
Internal Virtual Port for Medium
address the device via the port to which it is attached. These LUNs can be re-mapped to new LUNs for presentation via ports
1 and 2. Further, custom LUN maps can be simultaneously defined for individual hosts.
For example, the I/O blade may discover tape drives attached to ports 3–6, each of which report themselves at LUN 0. The
I/O blade could be configured to re-map these to LUNs 1, 2, 3, and 4 for discovery on ports 1 and 2. If desired, they could
also be simultaneously mapped to LUNs 3, 5, 7 and 9 for a specific host server.
There is also an internal (i.e., not attached to a port) controller device presented at LUN 0 by default. The controller device
facilitates initialization and device discovery. In some instances it may be useful to map the controller device to a different
LUN if an application typically expects to see a medium changer or tape drive at LUN 0.
LUNs can also be mapped to be accessible by specific host server World Wide Port Name (WWPN). Mapping a LUN to a
specific WWPN can be used instead of channel zoning to control device visibility. Mapping a LUN to more than one WWPN may
be useful for creating redundant paths to a medium changer, tape drive, or controller device. LUNs will need to be mapped to
each WWPN for host servers that use multiple ports (e.g., multi-ported HBAs or multiple HBAs) if access is desired via all the
host server ports (e.g., a LUN would need to be mapped to both WWPNs of a server that uses a dual-port HBA).
LUN masking is a complementary concept to host mapping in that LUNs that are mapped to specific host server WWPNs are
hidden (i.e., masked) from other host servers. This is useful when more than one host server is attached to the I/O blade
(e.g., in a SAN). One or more of the LUNs can be masked from discovery by specific host servers while maintaining their
mapping and accessibility to other host servers via the same port(s).
Host Mapping Vs. Channel Zoning
Channel zoning places an operational restriction on mapped LUNs (for example, if port 1 is zoned to ports 3 and 4, but LUNs
from ports 3 through 6 have been mapped to a specific host server WWPN, the devices on ports 5 and 6 cannot be accessed
from that host via port 1, even though they are mapped to it; only the devices on ports 3 and 4 would be accessible from the
host via port 1).
Host mapping can be used to control visibility of the medium changer devices found on the I/O blade internal virtual port,
while channel zoning can be used to create simple access control to the other target devices. If the host mapping capabilities
are used to control visibility and access for all the LUNs, channel zoning might not be necessary or desired.
Note:
On the operator panel, the host mapping screens (Setup > I/O Blades > Host Mapping) are not available
unless FC host mapping is enabled. See
Configuring Host Mapping
To configure host mapping, you need to select the partition, tape drive, or medium changer you want to map and assign a
new LUN number for the device.
Note:
Depending on host operating system constraints, it might be necessary to reboot or reconfigure the host due to
device mapping changes that result from configuring host mapping.
Details on configuring host mapping include:
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Host mapping is an optional feature and is disabled by default. For instructions on how to enable or disable host
mapping, see
Enabling/Disabling FC Host
The Setup - I/O Blade Host Mapping screen on the Web client lists the host name, I/O blade location, World Wide
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Port Name (WWPN), and operating system type of each available FC host. You can select the FC host to configure and
proceed to the next screen.
The screen lists the available partitions and tape drives connected to the I/O blade to which the FC host is attached.
file:///T|/htdocs/stor-sys/ML6000/en/html/ch04.htm[9/17/2012 1:49:29 PM]
Changers). Each of these devices has its own native logical unit number (LUN) that is used to
Enabling/Disabling FC Host
Mapping.
Mapping.
FC I/O Blade
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