You can easily manage the mapping of a LUN to hosts by assigning the host entries to a specific group. This group is a named, logical collection of hosts.
Your system might contain the following hosts:
Hosts that Oracle FS Path Manager (FSPM) registered, called FSPM host entries
Hosts that an administrator created by associating various initiators, called associated host entries
You can create more hosts by either using the
FSPM service or manually creating host entries. Creating host groups is useful if you have SAN host clusters, each of which contains many SAN hosts and each SAN host contains a few initiators.
If this SAN host cluster is not defined in the GUI as a host group, when you want to map a LUN to the cluster, map each host to the LUN one at a time. Furthermore, if you must move a SAN host to a different cluster, manually update each LUN mapping, also one at a time.
A more efficient method, however, is to define the cluster as a host group and then assign the hosts to the host group. When you later move a host from one host group to another, all the initiators that are associated with that host inherit the
LUN mappings associated with that host group.
Note: The Pilot automatically manages the deletion of the old mappings and the creation of the new initiator mappings.
Host groups have the following properties:
A host can belong to only one host group.
You can map unlimited hosts to a host group.
A host group can have zero or more mappings.
You can map a LUN to either a host or a host group.
If a host group has mappings, then all hosts in the host group have all of the mappings of the host group, but any given host may also have other mappings. No mappings may conflict with other mappings.
When assigning a host with mappings to a host group without mappings, you are prompted to migrate mappings on the host to the host group. Migrating these mappings make them available to all hosts in the group, not just the single host.
For example, consider the following host group (cluster) configuration:
- Host group Alpha
- LUN1 is mapped to this host group as LUN number 0.
- Host A
- Initiators A1 and A2 are mapped to LUN1. The LUN number is 0.
- Host B
- Initiators B1 and B2 are mapped to LUN1. The LUN number is 0.
- Host group Omega
- LUN2 is mapped to this host group as LUN number 0.
- Host C
- Initiators C1 and C2 are mapped to LUN2. The LUN number is 0.
If you move Host B from host group Alpha to host group Omega, the LUN mappings for Host B are automatically adjusted, as shown below:
- Host group Alpha
- LUN1 is mapped to this host group as LUN number 0.
- Host A
- Initiators A1 and A2 are mapped to LUN1. The LUN number is 0.
- Host group Omega
- LUN2 is mapped to this host group as LUN number 0.
- Host B
- Initiators B1 and B2 are mapped to LUN2. The LUN number is 0.
- Host C
- Initiators C1 and C2 are mapped to LUN2. The LUN number is 0.