Logical unit numbers for Fibre Channel ports

The system supports a maximum of 2048 logical unit numbers (LUNs) per I/O group, with a maximum of 512 configured to any one host.

You can map each volume that you create on the system to multiple HBA Fibre Channel ports in a specific host. There can also be multiple paths across the SAN. For these reasons, each host must run multipathing software, such as the Subsystem Device Driver (SDD). The multipathing software manages the many paths that are available to the volume and presents a single storage device to the operating system. The system supports various multipathing software packages. The specific multipathing software that the system supports depends on the host operating system that you use the software with.

• The number of paths through the network from the system nodes to a host must not exceed eight. Configurations that exceed this number are unsupported.
  • Each system node has multiple ports and each I/O group has two system nodes. Therefore, without any zoning, the number of paths to a volume is the number of system ports in the I/O group times the number of host ports.
  • This rule exists to limit the number of paths that must be resolved by the multipathing device driver.

If you want to restrict the number of paths to a host, zone the switches so that each HBA port is zoned with one system port for each node in the clustered system. If a host has multiple HBA ports, zone each port to a different set of system ports to maximize performance and redundancy.

For directly-attached host HBA ports, a connection must be made to each system node that has volumes that are mapped to that host.