6.0 HP X9000 File Serving Software File System User Guide (TA768-96043, October 2011)

How file allocation settings are evaluated
X9000 clients and NFS/CIFS clients use the following precedence rules to evaluate the file allocation
settings that are in effect for them:
• If the host uses the default file and directory allocation policies and segment preferences: The
RANDOM policy is applied, and a segment is chosen from among all segments.
• If the host uses a nondefault file and/or directory allocation policy and the default segment
preferences: Only the file or the directory allocation policy is applied, and a segment is chosen
from among the available segments.
• If the host uses a nondefault file and/or directory allocation policy and nondefault segment
preferences: A segment is chosen according to the following rules:
a. From the pool of preferred segments, select a segment according to the allocation policy
set for the client, and store the file in that segment if there is room. If all segments in the
pool are full, proceed to the next rule.
b. Use the AUTOMATIC allocation policy to choose a segment with enough storage room
from among the available segments, and store the file there.
Using hostgroups for file allocation settings
The file allocation commands include an option, -g GROUPLIST, that specifies one or more
hostgroups. This is 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.
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 on the management console. When X9000 Software services
start on a client, the client queries the management console 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 management console by executing ibrix_client or ibrix_lwhost
--a on the client, or by rebooting the client.
Guidelines for using file allocation CLI commands
Follow these guidelines when using CLI commands to perform any file allocation configuration
tasks:
• To perform a task for NFS/CIFS clients, specify NFS/CIFS servers for the -h HOSTLIST
argument.
• To perform a task for X9000 clients, either specify individual clients for the -h HOSTLIST
argument or specify a hostgroup for the -g GROUPLIST argument.
Setting file and directory allocation policies
You can set a nondefault file or directory allocation policy for NFS/CIFS servers and X9000 clients.
Before using the CLI commands to do this, see “Guidelines for using file allocation CLI commands”
(page 156).
You can specify the first segment where the policy should be applied, but in practice this is useful
only for the ROUNDROBIN policy.
Allocation policy names are case sensitive and must be entered as uppercase letters (for example,
RANDOM).
NOTE: If your file and directory allocation policies are different and you want to make them the
same, first verify that the file allocation policy is set correctly. Next, set the directory allocation
policy to NONE. The directory allocation policy then reverts to its default value, which is the policy
set for file allocation.
156 Using file allocation