This topic describes how SAN File System automates the management of files using policies and rules.
A policy is a set of rules that determine where specific files are placed based on the file's attributes. You can define any number of policies, but only one policy can be active at a time. If you switch from one policy to another or make changes to a policy, that action has no effect on existing files in the global namespace. The new or changed policy is effective only on newly created files in SAN File System. Manually moving a file does not cause the policy to be applied.
A policy can contain any number of rules. There is no limit to the size of a policy.
SAN File System performs error checking for file-placement policies in the following phases:
Currently, there is no error checking for file-management policies.
If your environment is set up in a non-uniform zone configuration (in which clients cannot access all volumes), you need to ensure that the rules in the active policy place files into volumes that are accessible to the clients that use them.
A rule is an SQL-like statement that tells the metadata server what to do with the data for a file in a specific storage pool if the file meets specific criteria. A rule can apply to any file being created or only to files being created within a specific fileset or group of filesets.
SAN File System evaluates rules in order, from top to bottom, as they appear in the active policy. The first rule that matches determines what is to be done with that file. For example, when a client creates a file, SAN File System scans the list of rules in the active file-placement policy to determine which rule applies to the file. When a rule applies to the file, SAN File System stops processing the rules and assigns the file to the appropriate storage pool. If no rule applies, the file is assigned to the default storage pool.
Parent topic: Storage management
Related concepts
Filesets
Storage pools
Related tasks
Creating a policy
Changing the rules in a policy
Viewing policy details
Viewing policy rules
Related reference
File placement policy syntax