Administrator Guide

Table 24. Available volume groups and volumes
Row description Group Name Type
A row with these values
appears for a volume/snapshot
that is grouped into a volume
group. Select this row to apply
map settings to all volumes/
snapshots in this volume group.
volume-group-name * Group
A row with these values
appears for each volume/
snapshot. Select this row to
apply map settings to this
volume/snapshot.
- volume-name volume-type
• When you select one or more host groups, hosts, or initiators in the Hosts topic, the items appears in the Available Host Groups,
Hosts, and Initiators table while all available volumes, volume groups, and snapshots appear in the Available Volume Groups and
Volumes table.
• The converse is true when you select one or more volumes, volume groups, or snapshots in the Available Volume Groups and
Volumes table.
• When you open the Map panel through the Mapping topic without selecting a mapping, both tables are fully populated with all
available items.
• When you select a mapping in the mapping table, it appears in the list of mappings below the above two tables. Also, both tables
are fully populated.
2. Perform one of the following:
• If nothing was pre-selected, select one or more initiators and one or more volumes to map and click the Map button.
• If initiators were pre-selected, select volumes to map to those initiators and click the Map button.
• If volumes were pre-selected, select initiators to map to those volumes and click the Map button.
• If maps were pre-selected, they already appear in the mapping table and a Map button appears.
For each pairing of selected initiators and volumes, a row appears in the mapping table at the bottom of the panel. At this time, no
further mappings can be added to the list. Mappings in the list can be modified—including the mapping's mode, LUN, or ports, or
they can be deleted.
NOTE:
Once a set of mappings between initiators and volumes have been defined using the Map button, the
button changes from Map to Reset. If mappings have been pre-selected, the Reset button, not the Map button,
appears.
3. Perform any of the following:
• To immediately remove a row from the table, in the Action column, select Remove Row.
• To delete an existing mapping, in the Action column, select Delete.
• To edit a mapping, set the following options:
○ Mode. The access mode can specify read-write access, read-only access, or no access to a volume. The default is read-write.
When a mapping specifies no access, the volume is masked, which means it is not visible to associated initiators. Masking is
useful to override an existing default map that allows open access so that access is denied only to specific initiators. To allow
access to specific hosts and deny access to all other hosts, create explicit maps to those hosts. For example, an engineering
volume could be mapped with read-write access for the engineering server and read-only access for servers used by other
departments.
○ LUN. The LUN identifies the volume to a host. The default is the lowest available LUN. Both controllers share one set of LUNs,
and any unused LUN can be assigned to a mapping. However, each LUN is generally only used once as a default LUN. For
example, if LUN 5 is the default for Volume1, no other volume in the storage system can use LUN 5 on the same port as its
default LUN. For explicit mappings, the rules differ: LUNs used in default mappings can be reused in explicit mappings for other
volumes and other hosts.
NOTE:
When mapping a volume to a host with the Linux ext3 file system, specify read-write access.
Otherwise, the file system will be unable to mount the volume and will report an error such as “unknown
partition table.”
○ Ports. Port selections specify controller host ports through which initiators are permitted to access, or are prevented from
accessing, the volume. Selecting a port number automatically selects the corresponding port in each controller.
• To save a new mapping or edits to an existing mapping, in the Action column, select Save.
• To clear the mapping table and discard any changes, click Reset.
Working in the Mappings topic
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