6.0 HP StorageWorks X9000 File Serving Software CLI Reference (TA768-96040, October 2011)

ibrix_fs_tune
Overrides the default file allocation behavior on file serving nodes and clients.
Description
X9000 Software allocates new files and directories to segments according to allocation policies
and segment preference settings that are in effect on the host that creates the file or directory. An
allocation policy controls segment selection. A segment preference setting overrides allocation
policies to prefer particular segments for storage.
By default, all file serving nodes and clients uses the RANDOM allocation policy and prefer all
segments for storing files. These defaults are well-suited to most needs. If an application requires
more sophisticated file allocation behavior, use ibrix_fs_tune to override the defaults as
follows:
• Change the default file and directory allocation policy (the available allocation policies are
listed in “File allocation policies” (page 54)).
• Prefer a pool of segments for storing all new files and directories.
• Declare the first segment in which a file or directory will be stored.
• Tune the allocation policy storage settings.
CAUTION: Changing the file allocation defaults will alter file-system storage behavior. Contact
HP technical support before changing any file allocation defaults.
NOTE: If your file and directory allocation policies are different and you want to make them the
same, first set a new file allocation policy, and then set the directory allocation policy to NONE.
The directory allocation policy assumes the value that is set for the file allocation policy. This is the
default directory allocation policy in effect until it is explicitly changed.
Because changes are specific to a given file system on a given host, different allocation policies
and preferences can be set for different file systems. You can also set different allocation policies
for files and directories, which can be useful for setting up data protection.
Allocation policies cannot be set on NFS and CIFS clients directly. They adhere to the policies set
on the NFS/CIFS servers to which they connect.
When a client creates a new file or directory, X9000 Software chooses a segment for storing it
according to the rule in effect for that node:
• Default allocation policy and segment preferences: X9000 Software applies the RANDOM
primary policy and chooses a segment from among all segments.
• For non-default allocation policy and default segment preferences, X9000 Software applies
the non-default allocation policy and chooses a segment from among all available segments.
• For non-default allocation policy and non-default segment preferences, X9000 Software
chooses the segment according to these precedence rules:
a. From the pool of preferred segments, select a segment according to the allocation policy
set for the client and store the file/directory there if space is available.
b. If all segments in the pool are full, use the AUTOMATIC algorithm to choose a segment
with enough space available.
Allocation policy changes are immediately executed on file serving nodes. For X9000 clients, a
policy intention is stored in the management console. When X9000 Software services start on a
client, the client queries the management console for the allocation policies that it should use and
then implements them. If X9000 Software services are already running on X9000 clients, you can
force clients to query the management console in one of the following ways: Execute
ibrix_fs_tune 53