Administrator Guide

The storage system uses Unified LUN Presentation (ULP), which can expose all LUNs through all host ports on both controllers.
The interconnect information is managed in the controller firmware. ULP appears to the host as an active-active storage system
where the host can choose any available path to access a LUN regardless of disk group ownership. When ULP is in use, the
controllers' operating/redundancy mode is shown as Active-Active ULP. ULP uses the T10 Technical Committee of INCITS
Asymmetric Logical Unit Access (ALUA) extensions, in SPC-3, to negotiate paths with aware host systems. Unaware host
systems see all paths as being equal.
If a host group or host is mapped to a volume or volume group, all of the initiators within that group will have an individual map
to each volume that makes up the request. As long as the group entity is mapped consistently, that set of individual maps will
be represented as a grouped mapping. If any individual map within that group is modified, the grouped mapping will no longer be
consistent, and it will no longer appear in the PowerVault Manager. It will be replaced in the PowerVault Manager with all of the
individual maps.
CAUTION: Volume mapping changes take effect immediately. Make changes that limit access to volumes when
the volumes are not in use. Before changing a LUN, be sure to unmount the volume.
NOTE: The secondary volume of a replication set cannot be mapped. Create a snapshot of the secondary volume or volume
group and use the snapshot for mapping and accessing data.
Map initiators and volumes
1. Perform one of the following:
● In the Hosts topic, select the initiators to map and select Action > Map Initiators.
● In the Volumes topic, select the volumes to map and select Action > Map Volumes.
● In the Mapping topic, select Map to create a new mapping.
● In the Mapping topic, select one or more mappings to modify or delete and select Action > Map. You can also create a
new mapping.
The Map panel opens and shows two tables side-by-side that list available initiators and volumes. You can use these tables
to create mappings. There is also a table underneath the host and volume tables that lists mappings. After you create a
mapping and before you save it, the mapping appears in the mappings table and you can modify its settings or delete it.
The Available Host Groups, Hosts, and Initiators table shows one or more of the following rows:
Table 23. Available host groups, hosts, and initiators
Row description Group Host Nickname ID
A row with these
values always appears.
Select this row to
apply map settings to
all initiators and create
a default mapping.
- - (blank) All Other
Initiators
A row with these
values appears for
an initiator that is
grouped into a host.
Select this row to
apply map settings to
all initiators in this
host.
- host-name * *
A row with these
values appears for
an initiator that is
grouped into a host
group. Select this row
to apply map settings
to all initiators in this
host group.
host-group-name * * *
A row with these
values appears for
each initiator. Select
- or host -
host-group-name
- or
host-name
(blank) or
initiator-nick
initiator-ID
Working in the Mappings topic 113