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, NVM Express® (NVMe) over Fibre Channel (FC-NVMe), NVM Express (NVMe) over RDMA, or an IP network. FC-NVMe connections require 4-port 16 GB Fibre Channel adapters that needs to be purchased. NVMe over RDMA connections require either 25 Gbps RoCE adapters, or 100 Gbps RoCE adapters, or some mixture of these adapters to be purchased and installed on the system.
- The 100 Gbps adapter supports iSCSI and NVMe over RDMA host attach protocols.
- For iSCSI, performance is limited to 25 Gbps per port.
- When both ports are used for NVMe over RDMA, I/O operation types are limited to 100 Gbps per adapter (not per port).
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. You must enter the WWPNs for such hosts manually. There is no equivalent list of candidate IQNs available when creating iSCSI hosts. All iSCSI host port IQNs must be entered 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.
A WWPN or iSCSI name can be added to only one host object or host cluster.
The system does not automatically present volumes to the host system. You must map each volume to a particular host object or host group to enable the volume to be accessed through the WWPNs or iSCSI names that are associated with the host object or host cluster.
For Fibre Channel, FC-NVMe, and NVMe over RDMA-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 or use the lsfabric command. To view connectivity issues for FC-NVMe and NVMe over RDMA-attached hosts in the management GUI, select or use the lsnvmefabric command.
- 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 and right-click the host and select IP Login Information. This information can be used to detect connectivity issues between the system and hosts and to improve the configuration of hosts to improve performance.
- To view login information in the command-line interface, use the lshostiplogin to list login session details for a specified host that is logged in to 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.
- You can also set a status policy and site status to determine how host statuses are displayed. For example, if you select Complete, the system displays an Online status only when all host ports are logged in to all nodes and hosts can access all mapped volumes. If a single host or node loses connectivity, the status for the host displays as Degraded. If you select Redundant for the Status Policy, an Online status is displayed when a sufficient number host ports to node logins exist to retain access to all its mapped volumes, even when a host port or single node is removed or lost.
- If hosts are part of a multiple site configuration, each host needs to be assigned to a specific site and you can specify how host statuses are displayed for these hosts. In the management GUI, you can specify All for Site Status to indicate that host connectivity to the nodes on all sites determine the status of the host. If you select Local for Site Status, the host status relates only to connectivity to nodes on the local site. Host status for other nodes mapped to different sites is not included.
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. Restricted users are those users who are defined to a specific ownership group and can only view or manage specific resources that are assigned to that ownership group. Unrestricted users are not defined to an ownership group and can manage any objects on the system based on their role on the system.
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:
- If a host is not part of a host cluster, an ownership group can be associated with the host when the host object is created or changed.
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:
- The host inherits the ownership group of the host cluster that it belongs to.
- If a host is removed from a host cluster within an ownership group, the host inherits the ownership group of the host cluster it used to belong to.
- If a host is removed from a host cluster not within an ownership group, the host inherits no ownership group.
- Hosts can be added to a host cluster if the host and host cluster have the same ownership group.
- Changing the ownership group of a host cluster automatically changes the ownership group of all the hosts inside the host cluster.
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.
Host portsets
Portsets are groupings of logical addresses that are associated with the specific traffic types. The system supports both Fibre Channel and IP portsets for host attachment, IP portsets for backend storage connectivity, and IP replication traffic. The system supports a maximum of 72 portsets.Requirements for Ethernet portsets
- Ethernet Portsets
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- Portsets are system-wide objects where IP addresses from all nodes might be included in the portset for host, storage, and replication functions.
- Each IP address in a portset must be configured on a separate Ethernet port.
- Same ports can share IP addresses across different portsets that allow the same IP address to be used for host, storage, and remote-copy traffic. All shared IP addresses must use the same port and have the same VLAN, gateway, and prefix. When IP addresses are shared among multiple portsets, the system creates a logical copy of the IP address and its attributes, rather than a new IP address.
- Portsets that are owned by different ownership groups can share an IP address.
- A port can have 64 unique or shared IP addresses. All 64 IP addresses can be IPv4 or IPv6, or a mix of IPv4 and IPv6.
- The Port Type field value defines if the portset is Ethernet. If you are using the command-line interface, specify ethernet in the port_type parameter of the mkportset command.
- Each port can be configured with only one unique routable IP address (gateway specified). The routable IP can be shared among multiple portsets.
- Portset 0 is a default portset that is automatically configured when the system is updated or created. Portset 0 is a host portset by default and cannot be deleted even if it is empty. Portset 0 serves as the default portset for any IP addresses and host objects that are configured without a portset specified. Portset 0 allows administrators to continue with an original configuration that does not require multi-tenancy. After an update, all configured Ethernet-based host objects are automatically mapped to portset 0.
Requirements for Fibre Channel portsets
The Fibre Channel portsets have the following requirements:
- Many host objects can be mapped to a single Fibre Channel portset.
- If you do not map a host object to a portset, host object is automatically mapped to the default portset to ensure operational continuity. The default portset for Fibre Channel portsets is portset64. You can create additional portsets based on the configurations and workload.
- Host objects can access volumes only through the Fibre Channel ports that are associated the respective portset.
- The Port Type field value defines if the portset is Fibre Channel. If you are using the command-line interface, specify fc in the port_type parameter of the mkportset command.
- The Fibre Channel I/O Ports are added to the portset using Fibre Channel I/O Port ID. It is applicable for all the nodes in the system.
- A Fibre Channel port can be associated with more than one portset.