A host group contains all the hosts connected to a storage system that have a specific OS and that are connected to the same port.
For example, if Linux hosts and Windows hosts are connected to the storage system, you must create one host group for the Linux hosts and another host group for the Windows hosts. It is helpful to give the host group a name associated with the host model. Then, you must register the host bus adapters (HBAs) of the Linux hosts in the Linux host group, and you must also register the HBAs of the Windows hosts in the Windows host group. A host group can contain only hosts that are connected to the same port. For example, if two Windows hosts are connected to port 1A and three Windows hosts are connected to port 1B, you cannot register all five Windows hosts in one host group. You must register the two Windows hosts on port 1A in one host group, and then register the three Windows hosts on port 1B in another host group.
You can connect multiple server hosts of different platforms to each port of your storage system. When configuring your storage system, you should group server hosts connected to the storage system by host groups. For example, if HP-UX hosts and Windows hosts are connected to a port, create one host group for HP-UX hosts and another host group for Windows hosts, and then register the HP-UX hosts to the HP-UX host group and register the Windows hosts to the Windows host group.
Notes on setting hosts (Fibre Channel)
You can set up to 255 host groups for each port. The maximum number of WWNs of HBAs that can be registered is 255 per host group, and 255 per Fibre Channel port.
Although the host mode setting operations do not involve data destruction, make sure to back up the data (data that can be accessed from the target port) before changing the host mode.
When registering multiple host groups or iSCSI targets on the same server in VSP One Block Administrator, set the same host mode and host mode options. You can verify the host groups or iSCSI targets registered on the VSP One Block Administrator server by using the raidcom get host_grp -key server command.
If you want to delete a host group, make sure to disable any enabled host mode options (HMOs) before the deletion. If HMOs 51 and 67 are set to enabled, the host group deletion fails. If the settings for HMOs 51 and 67 are changed, a link down or link up occurs. Therefore, if you want to change the port settings for the target CHB while connected to a host, make sure to verify the impact on the host, and then perform the maintenance operations during the time period during which the I/O load is low.
If the host group 0 (zero) is deleted or restored to its initial state, all WWNs belonging to the host group 0 are removed and all LU paths related to host group 0 are also removed. The host mode of host group 0 is set to 00 [Standard] and the host group name is initialized. For example, if you initialize host group 0 for the port CL1-A, the host group name changes to 1A-G00.