6.2 HP IBRIX 9000 Storage CLI Reference Guide (TA768-96070, December 2012)

ibrix_hostgroup
Creates and manages host groups.
Description
A host group is a named set of IBRIX 9000 clients. Host groups provide a convenient way to
centrally manage clients. Group-wide procedures include:
• Mounting file systems.
• Preferring or unpreferring a network interface for a host group. You can locally override the
preference on individual IBRIX 9000 clients with ibrix_lwhost.
• Tuning host parameters.
• Setting allocation policies.
When ibrix_mount, ibrix_host_tune, or ibrix_fs_tune is executed on a host group,
the command is stored on the Fusion Manager for each 9000 client until the next time a 9000
client contacts it. This happens when the 9000 client reboots, when IBRIX software services start
on the 9000 client, or when it is forced to query the Fusion Manager. When contacted, the Fusion
Manager replies to the IBRIX 9000 clients with information about commands that have been
executed on host groups to which they belong. The IBRIX 9000 clients then use this information to
mount file systems or implement host tunings or allocation policy settings.
To force a query on a 9000 client, execute ibrix_lwmount -a if you executed ibrix_mount
or ibrix_fs_tune on the host group, or run ibrix_lwhost --a if you executed
ibrix_host_tune.
All IBRIX 9000 clients belong to the default clients host group, which can be used to globally
mount file systems, tune hosts, or set allocation policy. To perform different actions on different sets
of IBRIX 9000 clients, create additional host groups and assign IBRIX 9000 clients to them. This
involves creating a host group tree whose root element is the clients host group. Each host
group in a tree can have exactly one parent, and a parent can have multiple children. To create
the first level of nodes beneath the root, execute ibrix_hostgroup -c -g GROUPNAME. To
create subsequent levels of nodes, execute ibrix_hostgroup -c -g GROUPNAME -p PARENT.
After creating a host group, assign IBRIX 9000 clients to it. You can do this manually or have the
Fusion Manager automatically assign the clients when they are registered. To set up automatic
host group assignments, define a domain rule for host groups. A domain rule restricts host group
membership to IBRIX 9000 clients on a particular cluster subnet. The Fusion Manager uses the IP
address that you specify for IBRIX 9000 clients when you register them to perform a subnet match
and sort the IBRIX 9000 clients into host groups based on domain rules. Setting domain rules on
host groups thus provides a convenient way to centrally manage mounting, tuning, and allocation
policies on different subnets of IBRIX 9000 clients.
In a host groups tree, operations performed on lower-level nodes take precedence over operations
performed on higher-level nodes. This means that you can effectively establish global 9000 client
mounts, host tunings, and allocation policies and then override them for specific host groups.
Synopsis
Create a host group tree:
ibrix_hostgroup -c -g GROUPNAME [-D DOMAIN] [-p PARENT]
To create one level of host groups beneath the root clients host group, execute the command
once for every host group that you want to add, but omit the -p PARENT option.
To create additional levels of host groups, execute the command for each host group to be added
and include the -p PARENT option.
To set a domain rule on a host group, include the -D DOMAIN option.
94 IBRIX software commands