6.1 HP IBRIX X9000 Network Storage System File System User Guide (TA768-96061, June 2012)

An X9000 client or X9000 file serving node (referred to as “the host”) uses the following precedence
rules to evaluate the file allocation settings that are in effect:
The host uses the default allocation policies and segment preferences: The RANDOM policy
is applied, and a segment is chosen from among ALL the available segments.
The host uses a non-default allocation policy (such as ROUNDROBIN) and the default segment
preference: Only the file or directory allocation policy is applied, and a segment is chosen
from among ALL available segments.
The host uses a non-default segment preference and a non-default allocation policy (such as
LOCAL/ROUNDROBIN): A segment is chosen according to the following rules:
From the pool of preferred segments, select a segment according to the allocation policy
set for the host, and store the file in that segment if there is room. If all segments in the
pool are full, proceed to the next rule.
Use the AUTOMATIC allocation policy to choose a segment with enough storage room
from among the available segments, and store the file.
When file allocation settings take effect on X9000 clients
Although file allocation settings are executed immediately on file serving nodes, for X9000 clients,
a file allocation intention is stored in the Fusion Manager. When X9000 Software services start
on a client, the client queries the Fusion Manager for the file allocation settings that it should use
and then implements them. If the services are already running on a client, you can force the client
to query the Fusion Manager by executing ibrix_client or ibrix_lwhost --a on the client,
or by rebooting the client.
Using CLI commands for file allocation
Follow these guidelines when using CLI commands to perform any file allocation configuration
tasks:
To perform a task for NAS clients (NFS, CIFS, FTP, HTTP), specify file serving nodes for the
-h HOSTLIST argument.
To perform a task for X9000 clients, specify individual clients for -h HOSTLIST or specify
a hostgroup for -g GROUPLIST. Hostgroups are a convenient way to configure file allocation
settings for a set of X9000 clients. To configure file allocation settings for all X9000 clients,
specify the clients hostgroup.
Setting file and directory allocation policies
You can set a nondefault file or directory allocation policy for file serving nodes and X9000 clients.
You can also specify the first segment where the policy should be applied, but in practice this is
useful only for the ROUNDROBIN policy.
IMPORTANT: Certain allocation policies are deprecated. See “File allocation policies (page 195)
for a list of standard allocation policies.
On the GUI, open the Modify Filesystem Properties dialog box and select the Host Allocation tab.
Setting file and directory allocation policies 197