Initiators, hosts and clusters

[johnnoakes]

When I map a lun, I can map it to initiator, or ig I have created a host to that host or i guess if i have created a cluster to a cluster.

Is this just a gui thing? If I have mapped 3 luns as initiators to 3 hosts, then 1 lun to same hosts as hosts. If I create a cluster of these 3 hosts and maps a 4th lun to the cluster. Does it matters? Is it just to simplyfie things in gui?

[SUBHAJIT KHANBARMAN_1]

I would suggest you to go through SMU guide to get details on the same,

https://support.hpe.com/hpsc/doc/public/display?docId=a00017707en_us

For MSA1050/2050 you can refer the above link and check section "About initiators, hosts, and host groups", "Working in the Mappings topic", "Mapping initiators and volumes"

Some important portion captured from SMU guide related to your query as below,

"For ease of management, you can group 1–128 initiators that represent a server into a host. Further, you can group 1–256
hosts into a host group. Doing so enables you to perform mapping operations for all initiators in a host, or all initiators
and hosts in a group, instead of for each initiator or host individually. An initiator must have a nickname to be added to a
host, and an initiator can be a member of only one host. A host can be a member of only one group. A host cannot have
the same name as another host, but can have the same name as any initiator. A host group cannot have the same name
as another host group, but can have the same name as any host. A maximum of 32 host groups can exist."

"If a group (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 SMU. It will be replaced in the SMU with
all of the individual maps."

It's not about SMU or GUI only, mapping, group all possible from CLI as well. You can refer CLI guide and search for command "map volume".

Hope this helps!
Regards
Subhajit

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[johnnoakes]

Thank you.
But is it safe to add already mapped initiators/hosts to a group?

My native language is not english so manual may provide that info, but I do not understand :-)

[SUBHAJIT KHANBARMAN_1]

You can add existing hosts to an existing host group or new host group.

To add a host to a host group, the host must have the same mappings as all other members of the group. This means that the host must be mapped with the same access, port, and LUN settings to the same volumes or volume groups.

You can refer SMU guide section "Adding hosts to a host group" to get more details on this.

You search SMU guide in your language to understand all details. What is your native language ?

Hope this helps!
Regards
Subhajit

If you feel this was helpful please click the KUDOS! thumb below!

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