Creating Host Groups For 9000 Clients; How Host Groups Work; Creating A Host Group Tree - HP IBRIX 9300 Administrator's Manual

7 Creating host groups for 9000 clients

A host group is a named set of 9000 clients. Host groups provide a convenient way to centrally
manage clients. You can put different sets of clients into host groups and then perform the following
operations on all members of the group:
Create and delete mount points
Mount file systems
Prefer a network interface
Tune host parameters
Set allocation policies
Host groups are optional. If you do not choose to set them up, you can mount file systems on clients
and tune host settings and allocation policies on an individual level.

How host groups work

In the simplest case, the host groups functionality allows you to perform an allowed operation on
all 9000 clients by executing a command on the default clients host group with the CLI or the
GUI. The clients host group includes all 9000 clients configured in the cluster.
NOTE: The command intention is stored on the Fusion Manager until the next time the clients
contact the Fusion Manager. (To force this contact, restart IBRIX software services on the clients,
reboot the clients, or execute ibrix_lwmount -a or ibrix_lwhost --a.) When contacted,
the Fusion Manager informs the clients about commands that were executed on host groups to
which they belong. The clients then use this information to perform the operation.
You can also use host groups to perform different operations on different sets of clients. To do this,
create a host group tree that includes the necessary host groups. You can then assign the clients
manually, or the Fusion Manager can automatically perform the assignment when you register an
IBRIX 9000 client, based on the client's cluster subnet. To use automatic assignment, create a
domain rule that specifies the cluster subnet for the host group.

Creating a host group tree

The clients host group is the root element of the host group tree. Each host group in a tree can
have only one parent, but a parent can have multiple children. In a host group tree, operations
performed on lower-level nodes take precedence over operations performed on higher-level nodes.
This means that you can effectively establish global client settings that you can override for specific
clients.
For example, suppose that you want all clients to be able to mount file system ifs1 and to
implement a set of host tunings denoted as Tuning 1, but you want to override these global settings
for certain host groups. To do this, mount ifs1 on the clients host group, ifs2 on host group
A, ifs3 on host group C, and ifs4 on host group D, in any order. Then, set Tuning 1 on the
clients host group and Tuning 2 on host group B. The end result is that all clients in host group
B will mount ifs1 and implement Tuning 2. The clients in host group A will mount ifs2 and
implement Tuning 1. The clients in host groups C and D respectively, will mount ifs3 and ifs4
and implement Tuning 1. The following diagram shows an example of these settings in a host
group tree.
How host groups work 63