Hosts

A host system is a computer that is connected to the system through supported connection protocols. The system supports host connections through Fibre Channel, Fibre Channel over Ethernet, NVM Express (NVMe) over Fibre Channel (FC-NVMe), or an IP network. To use Fibre Channel or Fibre Channel over Ethernet connections to a storage area network (SAN), an optional host interface adapter must be installed on the system. FC-NVMe connections require 4-port 16 GB Fibre Channel adapters, which are usually preinstalled on the system.

A host object is a logical object that represents a list of worldwide port names (WWPNs), NVMe qualified names (NQNs), or iSCSI or iSER names that identify the interfaces that the host system uses to communicate with the system. Fibre Channel connections or Fibre Channel over Ethernet use WWPNs to identify host interfaces to the system. iSCSI or iSER names can be either iSCSI qualified names (IQNs) or extended unique identifiers (EUIs). NQNs are used to identify hosts that use FC-NVMe connections.

A typical configuration has one host object for each host system that is attached to the system. If a cluster of hosts accesses the same storage, you can add the hosts into a host cluster object to make configuration simpler.

When you create a new Fibre Channel host object, the system presents a list of candidate WWPNs that have been logged into the system but are not yet configured in host objects. Some Fibre Channel HBA device drivers do not leave their ports logged in if no disks are detected on the fabric, so they are not visible in the list of candidate ports. You must enter the WWPNs for such hosts manually.

The system can detect only WWPNs that have connected to the system through the Fibre Channel network or through any IP network. Some Fibre Channel HBA device drivers do not leave ports logged in if no disks are detected on the fabric or IP network. The configuration interface provides a method to manually type the port names.

The system does not automatically present volumes to the host system. You must map each volume to a host object to enable the volume to be accessed through the WWPNs, NQNs, or iSCSI or iSER names that are associated with the host object. For Fibre Channel or FC-NVMe-attached hosts, the system reports the node login count, which is the number of nodes that can detect each WWPN or NQN. If the count is less than expected for the current configuration, you might have a connectivity problem. To view potential connectivity issues for Fiber Channel-attached hosts in the management GUI, select Settings > Network > Fibre Channel Connectivity or use the lsfabric command. To view connectivity issues for FC-NVMe-attached hosts in the management GUI, select Settings > Network > NVMe Connectivity or use the lsnvmefabric command. For iSCSI or iSER-attached hosts, the number of logged-in nodes refers to iSCSI or iSER sessions that are created between hosts and nodes, and might be greater than the current number of nodes on the system. You can display the login information for each host in the management GUI to determine which ports for the logged-in nodes are connected to the Ethernet-attached hosts. To display this information, select Hosts > Hosts and right-click the host and select IP Login Information. To view login information in the command-line interface, use the lshostiplogin to list login session details for a specified host that is logged into a configured Ethernet port on the system. This information can be used to detect connectivity issues between the system and hosts and to improve the configuration of hosts to improve performance.

Hosts can be assigned to an ownership group. An ownership group defines a subset of users and objects within the system. You can create ownership groups to further restrict access to specific resources that are defined in the ownership group. Only users with Security Administrator roles can configure and manage ownership groups.

Ownership can be defined explicitly or it can be inherited from the user, user group, or from other parent resources, depending on the type of resource. Hosts that are not part of a host cluster can be owned if they are assigned an ownership group explicitly or by inheritance from the user creating them. The following rules apply to hosts that are not part of a host cluster that is defined in ownership groups:

Hosts that are a part of a host cluster inherit ownership from the host cluster. A user cannot change the ownership group of the host, but can change the ownership group of the host cluster. The following rules apply to hosts that are in a host cluster:

Port masks

You can use the port-mask property of the host object to control the Fibre Channel ports on each system node that a host can access. The port mask applies to logins from the WWPNs that are associated with the host object. The port-mask configuration has no effect on iSCSI or iSER connections.

For each login between a host Fibre Channel port and node Fibre Channel port, the node examines the port mask for the associated host object and determines if access is allowed or denied. If access is denied, the node responds to SCSI commands as if the HBA WWPN is unknown.

The port mask is 64 bits. Valid mask values range from all 0s (no ports enabled) to all 1s (all ports enabled). For example, a mask of 0011 enables port 1 and port 2. The default value is all 1s.

Multiple target ports

When you create a host mapping to a host, the host ports that are associated with the host object can view the LUN that represents the volume on many ports. Nodes follow the American National Standards Institute (ANSI) Fibre Channel (FC) standards for SCSI LUs that are accessed through multiple node ports. All nodes within a single I/O group present a consistent set of SCSI LUs across all ports on those nodes.